|
|
Modular Connectors / Ethernet Connectors 10/100 1X1 INV. 1.90 mm Pin
- 5-2301994-1
- TE Connectivity
-
1:
$5.85
-
4,003In Stock
|
Mouser Part No
571-5-2301994-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors 10/100 1X1 INV. 1.90 mm Pin
|
|
4,003In Stock
|
|
|
$5.85
|
|
|
$4.98
|
|
|
$4.68
|
|
|
$4.44
|
|
|
View
|
|
|
$4.22
|
|
|
$4.05
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Magnetic Jack
|
Jack (Female)
|
RJ45
|
1x1
|
8P8C
|
Shielded, EMI Fingers
|
Cat 5
|
Through Hole
|
Right Angle
|
Solder
|
|
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Up
|
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors 2 X 3 8 POS R/A
- 5569261-1
- TE Connectivity / Alcoswitch
-
1:
$28.09
-
1,042In Stock
|
Mouser Part No
571-5569261-1
|
TE Connectivity / Alcoswitch
|
Modular Connectors / Ethernet Connectors 2 X 3 8 POS R/A
|
|
1,042In Stock
|
|
|
$28.09
|
|
|
$23.92
|
|
|
$22.93
|
|
|
$22.40
|
|
|
View
|
|
|
$21.90
|
|
|
$21.57
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
2x3
|
8P8C
|
Shielded, EMI Fingers
|
Cat 5
|
Through Hole
|
Right Angle
|
Solder
|
|
200 mA, 1.5 A
|
150 V
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Up and Tab Down
|
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors 2 X 4 8 POS R/A
- 5569262-1
- TE Connectivity
-
1:
$21.62
-
1,114In Stock
|
Mouser Part No
571-5569262-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors 2 X 4 8 POS R/A
|
|
1,114In Stock
|
|
|
$21.62
|
|
|
$20.49
|
|
|
$18.97
|
|
|
$18.29
|
|
|
View
|
|
|
$17.42
|
|
|
$16.90
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
2x4
|
8P8C
|
Shielded, EMI Fingers
|
Cat 5
|
Through Hole
|
Right Angle
|
Solder
|
|
200 mA, 1.5 A
|
150 V
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Up and Tab Down
|
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors INDUSTRIAL MINI I/O HDR TYPE I TRAY
- 2294415-1
- TE Connectivity
-
1:
$4.83
-
22,238In Stock
|
Mouser Part No
571-2294415-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors INDUSTRIAL MINI I/O HDR TYPE I TRAY
|
|
22,238In Stock
|
|
|
$4.83
|
|
|
$4.44
|
|
|
$4.18
|
|
|
$3.98
|
|
|
View
|
|
|
$3.78
|
|
|
$3.50
|
|
|
$3.38
|
|
|
$2.98
|
|
|
$2.65
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
1x1
|
|
Shielded
|
|
Through Hole
|
Right Angle
|
SMD/SMT
|
|
500 mA
|
60 VAC
|
- 40 C
|
+ 85 C
|
|
|
|
INDUSTRIAL MINI I/O
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors RJ45 JACK INT.MAG. 1GB LED 1X1 VERT.
- 5-2301995-4
- TE Connectivity
-
1:
$9.49
-
7,754In Stock
|
Mouser Part No
571-5-2301995-4
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors RJ45 JACK INT.MAG. 1GB LED 1X1 VERT.
|
|
7,754In Stock
|
|
|
$9.49
|
|
|
$8.37
|
|
|
$7.84
|
|
|
$7.47
|
|
|
$7.16
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Magnetic Jack
|
Jack (Female)
|
RJ45
|
1x1
|
8P8C
|
Shielded
|
Cat 6
|
Through Hole
|
Vertical
|
Solder
|
|
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Top Entry
|
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors 8P Shielded Invert Modular Jack
- 1705549-1
- TE Connectivity / AMP
-
1:
$3.27
-
2,803In Stock
|
Mouser Part No
571-1705549-1
|
TE Connectivity / AMP
|
Modular Connectors / Ethernet Connectors 8P Shielded Invert Modular Jack
|
|
2,803In Stock
|
|
|
$3.27
|
|
|
$2.79
|
|
|
$2.49
|
|
|
$2.37
|
|
|
$2.04
|
|
|
View
|
|
|
$1.99
|
|
|
$1.97
|
|
|
$1.93
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
1x1
|
8P8C
|
Unshielded
|
Cat 3
|
PCB Mount
|
Vertical
|
SMD/SMT
|
|
1.5 A
|
|
- 40 C
|
+ 70 C
|
Black
|
|
Top Entry
|
|
Reel, Cut Tape, MouseReel
|
|
|
|
Modular Connectors / Ethernet Connectors MJ,RJ4,5SM,TSHLD LED (G/O)
- 2-6339191-1
- TE Connectivity
-
1:
$7.72
-
1,538In Stock
|
Mouser Part No
571-2-6339191-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors MJ,RJ4,5SM,TSHLD LED (G/O)
|
|
1,538In Stock
|
|
|
$7.72
|
|
|
$6.56
|
|
|
$6.15
|
|
|
$5.86
|
|
|
$5.15
|
|
|
View
|
|
|
$5.41
|
|
|
$5.00
|
|
|
$4.95
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
|
RJ45
|
1x1
|
8P8C
|
Shielded, EMI Fingers
|
Cat 5
|
PCB Mount
|
Right Angle
|
SMD/SMT
|
|
1.5 A
|
|
- 40 C
|
+ 85 C
|
Black
|
Green / Orange
|
Tab Up
|
|
Reel, Cut Tape, MouseReel
|
|
|
|
Modular Connectors / Ethernet Connectors INDUSTRIAL MINI I/O PIERCING PLG CON KIT
- 2201855-3
- TE Connectivity
-
1:
$13.35
-
242In Stock
|
Mouser Part No
571-2201855-3
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors INDUSTRIAL MINI I/O PIERCING PLG CON KIT
|
|
242In Stock
|
|
|
$13.35
|
|
|
$11.34
|
|
|
$10.63
|
|
|
$10.12
|
|
|
View
|
|
|
$9.64
|
|
|
$9.16
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Mini Connector
|
Plug (Male)
|
|
|
8P8C
|
Shielded
|
Cat 5e
|
Cable Mount
|
Straight
|
IDC
|
|
1.5 A
|
30 VAC
|
- 40 C
|
+ 85 C
|
Black
|
|
User Selectable
|
INDUSTRIAL MINI I/O
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors MJ,RJ11,SMT,6/6,GRAY 22"REEL
- 5406514-1
- TE Connectivity
-
1:
$2.54
-
1,583In Stock
|
Mouser Part No
571-5406514-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors MJ,RJ11,SMT,6/6,GRAY 22"REEL
|
|
1,583In Stock
|
|
|
$2.54
|
|
|
$2.15
|
|
|
$1.92
|
|
|
$1.83
|
|
|
$1.65
|
|
|
View
|
|
|
$1.72
|
|
|
$1.50
|
|
|
$1.47
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
|
RJ11
|
1x1
|
6P6C
|
Unshielded
|
Cat 3
|
PCB Mount
|
Right Angle
|
SMD/SMT
|
|
1.5 A
|
|
- 40 C
|
+ 70 C
|
Gray
|
|
Tab Up
|
|
Reel, Cut Tape, MouseReel
|
|
|
|
Modular Connectors / Ethernet Connectors 1 PORT CAT 5
- 5558341-1
- TE Connectivity
-
1:
$3.68
-
1,822In Stock
|
Mouser Part No
571-5558341-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors 1 PORT CAT 5
|
|
1,822In Stock
|
|
|
$3.68
|
|
|
$3.13
|
|
|
$2.79
|
|
|
$2.67
|
|
|
$2.62
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
|
RJ45
|
1x1
|
8P8C
|
Unshielded
|
Cat 5e
|
Through Hole
|
Right Angle
|
Solder
|
|
200 mA, 1.5 A
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Down
|
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors STK MJ,2X1,SHLD Y/G/Y/G LEDS
- 6368011-5
- TE Connectivity / AMP
-
1:
$22.12
-
947In Stock
|
Mouser Part No
571-6368011-5
|
TE Connectivity / AMP
|
Modular Connectors / Ethernet Connectors STK MJ,2X1,SHLD Y/G/Y/G LEDS
|
|
947In Stock
|
|
|
$22.12
|
|
|
$19.39
|
|
|
$18.25
|
|
|
$17.86
|
|
|
View
|
|
|
$17.63
|
|
|
$17.46
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
|
RJ45
|
2x1
|
8P8C
|
Shielded, EMI Fingers
|
Cat 5
|
Through Hole
|
Right Angle
|
Solder
|
|
200 mA, 1.5 A
|
|
- 40 C
|
+ 85 C
|
Black
|
Yellow / Green
|
Tab Up and Tab Down
|
|
|
|
|
|
Modular Connectors / Ethernet Connectors RJ45 8P8C SHD W/ LED DIP 6u
- 1-1734795-1
- TE Connectivity
-
1:
$2.93
-
1,851In Stock
|
Mouser Part No
571-1-1734795-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors RJ45 8P8C SHD W/ LED DIP 6u
|
|
1,851In Stock
|
|
|
$2.93
|
|
|
$2.66
|
|
|
$2.47
|
|
|
$2.33
|
|
|
View
|
|
|
$2.20
|
|
|
$2.14
|
|
|
$2.01
|
|
|
$1.97
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
1x1
|
8P8C
|
Shielded
|
Cat 3
|
Through Hole
|
Right Angle
|
Solder
|
|
1 A
|
|
- 40 C
|
+ 85 C
|
Black
|
Yellow / Green
|
Tab Up
|
|
|
|
|
|
Modular Connectors / Ethernet Connectors 6 RND PLUG ASSY 50 SERIES
- 1-520424-2
- TE Connectivity
-
1:
$5.58
-
451In Stock
|
Mouser Part No
571-1-520424-2
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors 6 RND PLUG ASSY 50 SERIES
|
|
451In Stock
|
|
|
$5.58
|
|
|
$5.04
|
|
|
$4.87
|
|
|
$4.68
|
|
|
View
|
|
|
$4.49
|
|
|
$4.16
|
|
|
$3.92
|
|
|
$3.74
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Shielded
|
|
|
|
4P4C
|
Shielded
|
|
Cable Mount
|
Straight
|
IDC
|
|
1.5 A
|
|
- 20 C
|
+ 80 C
|
Gray
|
|
|
|
|
|
|
|
Modular Connectors / Ethernet Connectors 1X1 6/6 R/A LPRO
- 5555140-1
- TE Connectivity
-
1:
$2.02
-
2,983In Stock
|
Mouser Part No
571-5555140-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors 1X1 6/6 R/A LPRO
|
|
2,983In Stock
|
|
|
$2.02
|
|
|
$1.72
|
|
|
$1.54
|
|
|
$1.23
|
|
|
View
|
|
|
$1.16
|
|
|
$1.14
|
|
|
$1.12
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ25
|
1x1
|
6P6C
|
Shielded
|
Cat 3
|
Through Hole
|
Right Angle
|
Solder
|
|
200 mA, 1.5 A
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Down
|
555
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors 6/4 PBC LO PRO R/A
- 5555165-2
- TE Connectivity
-
1:
$1.13
-
3,605In Stock
|
Mouser Part No
571-5555165-2
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors 6/4 PBC LO PRO R/A
|
|
3,605In Stock
|
|
|
$1.13
|
|
|
$0.962
|
|
|
$0.859
|
|
|
$0.795
|
|
|
$0.776
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ14
|
1x1
|
6P4C
|
Unshielded
|
Cat 3
|
Through Hole
|
Right Angle
|
Solder
|
|
200 mA, 1.5 A
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Down
|
555
|
|
|
|
|
Modular Connectors / Ethernet Connectors RECPT WITH PC BOARD
- 1-1546409-1
- TE Connectivity
-
1:
$77.55
-
67In Stock
|
Mouser Part No
571-1-1546409-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors RECPT WITH PC BOARD
|
|
67In Stock
|
|
|
$77.55
|
|
|
$65.91
|
|
|
$61.78
|
|
|
$60.63
|
|
Min.: 1
Mult.: 1
|
|
|
Couplers
|
Circular
|
Jack (Female)
|
RJ45
|
1x1
|
8P8C
|
Shielded
|
Cat 5e
|
Panel Mount
|
Straight
|
|
|
1.5 A
|
|
- 20 C
|
+ 80 C
|
Black
|
|
User Selectable
|
|
|
|
|
|
Modular Connectors / Ethernet Connectors 8 POS 1X1 RJ45 VERT SMT
- 1-338088-6
- TE Connectivity / AMP
-
1:
$2.42
-
1,383In Stock
|
Mouser Part No
571-1-338088-6
|
TE Connectivity / AMP
|
Modular Connectors / Ethernet Connectors 8 POS 1X1 RJ45 VERT SMT
|
|
1,383In Stock
|
|
|
$2.42
|
|
|
$2.06
|
|
|
$1.84
|
|
|
$1.76
|
|
|
$1.44
|
|
|
View
|
|
|
$1.42
|
|
|
$1.41
|
|
|
$1.40
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
1x1
|
8P8C
|
Unshielded
|
Cat 3
|
PCB Mount
|
Straight
|
SMD/SMT
|
|
1.5 A
|
|
- 45 C
|
+ 70 C
|
Black
|
|
Top Entry
|
|
Reel, Cut Tape, MouseReel
|
|
|
|
Modular Connectors / Ethernet Connectors RJ11 6P 6C SINGLE DIP 15u Au Reel
- 1734723-6
- TE Connectivity / AMP
-
1:
$4.06
-
1,173In Stock
|
Mouser Part No
571-1734723-6
|
TE Connectivity / AMP
|
Modular Connectors / Ethernet Connectors RJ11 6P 6C SINGLE DIP 15u Au Reel
|
|
1,173In Stock
|
|
|
$4.06
|
|
|
$3.70
|
|
|
$3.50
|
|
|
$3.26
|
|
|
View
|
|
|
$2.84
|
|
|
$2.76
|
|
|
$2.19
|
|
|
$2.11
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
|
RJ25
|
1x1
|
6P6C
|
Shielded
|
Cat 3
|
Through Hole
|
Right Angle
|
Solder
|
|
1 A
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Down
|
|
|
|
|
|
Modular Connectors / Ethernet Connectors 8P/8C INV MJ SMT 22 TOP REEL
- 2-338088-3
- TE Connectivity / AMP
-
1:
$1.44
-
1,398In Stock
|
Mouser Part No
571-2-338088-3
|
TE Connectivity / AMP
|
Modular Connectors / Ethernet Connectors 8P/8C INV MJ SMT 22 TOP REEL
|
|
1,398In Stock
|
|
|
$1.44
|
|
|
$1.33
|
|
|
$1.24
|
|
|
$1.13
|
|
|
$1.12
|
|
|
$1.10
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
|
RJ45
|
1x1
|
8P8C
|
Unshielded
|
Cat 3
|
PCB Mount
|
Straight
|
SMD/SMT
|
|
1.5 A
|
|
- 40 C
|
+ 70 C
|
Black
|
|
Top Entry
|
|
Reel, Cut Tape, MouseReel
|
|
|
|
Modular Connectors / Ethernet Connectors 8 RND PLUG BOOT
- 520853-1
- TE Connectivity
-
1:
$2.54
-
1,168In Stock
|
Mouser Part No
571-520853-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors 8 RND PLUG BOOT
|
|
1,168In Stock
|
|
|
$2.54
|
|
|
$2.44
|
|
|
$2.17
|
|
|
$2.08
|
|
|
View
|
|
|
$1.95
|
|
|
$1.85
|
|
|
$1.71
|
|
|
$1.65
|
|
Min.: 1
Mult.: 1
|
|
|
Accessories
|
Boot
|
Plug (Male)
|
|
|
8P8C
|
|
|
Cable Mount
|
Straight
|
|
|
|
|
|
|
Black
|
|
|
|
Bulk
|
|
|
|
Modular Connectors / Ethernet Connectors 6 POS RJ25 TOP ENTRY
- 5554990-1
- TE Connectivity / AMP
-
1:
$1.74
-
1,855In Stock
|
Mouser Part No
571-5554990-1
|
TE Connectivity / AMP
|
Modular Connectors / Ethernet Connectors 6 POS RJ25 TOP ENTRY
|
|
1,855In Stock
|
|
|
$1.74
|
|
|
$1.56
|
|
|
$1.45
|
|
|
$1.35
|
|
|
View
|
|
|
$1.28
|
|
|
$1.22
|
|
|
$1.09
|
|
|
$1.06
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ25
|
1x1
|
6P6C
|
Unshielded
|
Cat 3
|
Through Hole
|
Vertical
|
Solder
|
|
200 mA, 1.5 A
|
150 V
|
- 40 C
|
+ 85 C
|
Gray
|
|
Top Entry
|
555
|
Tray
|
|
|
|
Modular Connectors / Ethernet Connectors RJ45 SMT SHLD G/Y
- 6339191-4
- TE Connectivity
-
1:
$6.01
-
588In Stock
|
Mouser Part No
571-6339191-4
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors RJ45 SMT SHLD G/Y
|
|
588In Stock
|
|
|
$6.01
|
|
|
$5.29
|
|
|
$4.98
|
|
|
$4.80
|
|
|
$3.81
|
|
|
View
|
|
|
$4.12
|
|
|
$3.65
|
|
|
$3.47
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
|
RJ45
|
1x1
|
8P8C
|
Shielded, EMI Fingers
|
Cat 5
|
PCB Mount
|
Right Angle
|
SMD/SMT
|
|
1.5 A
|
|
- 40 C
|
+ 85 C
|
Black
|
Green / Yellow
|
Tab Up
|
|
Reel, Cut Tape, MouseReel
|
|
|
|
Modular Connectors / Ethernet Connectors MJ, INV, 1X1, 0PNL G, .100"ST, SN
- 1-406541-8
- TE Connectivity
-
1:
$4.99
-
1,070In Stock
|
Mouser Part No
571-1-406541-8
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors MJ, INV, 1X1, 0PNL G, .100"ST, SN
|
|
1,070In Stock
|
|
|
$4.99
|
|
|
$4.24
|
|
|
$3.98
|
|
|
$3.79
|
|
|
$3.28
|
|
|
$3.08
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
1x1
|
8P8C
|
Shielded
|
Cat 5
|
Through Hole
|
Right Angle
|
Solder
|
|
200 mA, 1.5 A
|
|
- 45 C
|
+ 85 C
|
Black
|
|
Tab Up
|
|
Reel, Cut Tape
|
|
|
|
Modular Connectors / Ethernet Connectors RJ11 6P6C SINGLE DIP W/O LED 6u
- 1734723-1
- TE Connectivity
-
1:
$3.04
-
1,903In Stock
|
Mouser Part No
571-1734723-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors RJ11 6P6C SINGLE DIP W/O LED 6u
|
|
1,903In Stock
|
|
|
$3.04
|
|
|
$2.59
|
|
|
$2.31
|
|
|
$2.17
|
|
|
View
|
|
|
$2.00
|
|
|
$1.93
|
|
|
$1.85
|
|
|
$1.76
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ25
|
1x1
|
6P6C
|
Shielded
|
Cat 3
|
Through Hole
|
Right Angle
|
Solder
|
|
1 A
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Down
|
|
|
|
|
|
Modular Connectors / Ethernet Connectors RJ45 OVER RCPT USB
- 1775855-1
- TE Connectivity
-
1:
$4.15
-
853In Stock
|
Mouser Part No
571-1775855-1
|
TE Connectivity
|
Modular Connectors / Ethernet Connectors RJ45 OVER RCPT USB
|
|
853In Stock
|
|
|
$4.15
|
|
|
$3.31
|
|
|
$3.14
|
|
|
$2.99
|
|
|
View
|
|
|
$2.76
|
|
|
$2.67
|
|
|
$2.52
|
|
|
$2.47
|
|
Min.: 1
Mult.: 1
|
|
|
Connectors
|
Modular
|
Jack (Female)
|
RJ45
|
RJ45 over USB Type A
|
8P8C
|
Shielded
|
Cat 3
|
Through Hole
|
Right Angle
|
Solder
|
|
1 A, 1.5 A
|
|
- 40 C
|
+ 85 C
|
Black
|
|
Tab Up
|
|
Tray
|
|
South Africa