|
|
Headers & Wire Housings 6 POS R/A SHRD HDR THRU MNT SINGLE ROW
- 78208-406HLF
- Amphenol FCI
-
1:
$0.89
-
1,858In Stock
|
Mouser Part No
649-78208-406HLF
|
Amphenol FCI
|
Headers & Wire Housings 6 POS R/A SHRD HDR THRU MNT SINGLE ROW
|
|
1,858In Stock
|
|
|
$0.89
|
|
|
$0.759
|
|
|
$0.729
|
|
|
$0.713
|
|
|
View
|
|
|
$0.683
|
|
|
$0.62
|
|
|
$0.558
|
|
|
$0.508
|
|
|
$0.465
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Shrouded
|
6 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Tin
|
5.84 mm (0.23 in)
|
3.5 mm (0.138 in)
|
BergStik
|
BergStik
|
Wire-to-Board
|
|
- 40 C
|
+ 95 C
|
Bulk
|
|
|
|
Headers & Wire Housings GUIDE PIN CARD CONN
- 66527-017
- Amphenol FCI
-
1:
$6.30
-
224In Stock
|
Mouser Part No
649-66527-017
|
Amphenol FCI
|
Headers & Wire Housings GUIDE PIN CARD CONN
|
|
224In Stock
|
|
|
$6.30
|
|
|
$5.75
|
|
|
$5.42
|
|
|
$5.30
|
|
|
View
|
|
|
$4.49
|
|
|
$4.41
|
|
|
$4.29
|
|
|
$3.68
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Receptacle
|
34 Position
|
2.54 mm (0.1 in)
|
2 Row
|
2.54 mm (0.1 in)
|
Through Hole
|
Solder Pin
|
Right Angle
|
Socket (Female)
|
Gold
|
|
2.92 mm (0.115 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Tube
|
|
|
|
Headers & Wire Housings 16P SR RA SHRD HDR .76 GOLD
- 76382-316LF
- Amphenol FCI
-
1:
$2.64
-
585In Stock
|
Mouser Part No
649-76382-316LF
|
Amphenol FCI
|
Headers & Wire Housings 16P SR RA SHRD HDR .76 GOLD
|
|
585In Stock
|
|
|
$2.64
|
|
|
$2.30
|
|
|
$2.20
|
|
|
$2.15
|
|
|
View
|
|
|
$2.06
|
|
|
$1.86
|
|
|
$1.71
|
|
|
$1.37
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Shrouded
|
16 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
5 mm (0.197 in)
|
3.43 mm (0.135 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 40 C
|
+ 125 C
|
Tube
|
|
|
|
Headers & Wire Housings LATCHING HDR 20 POSI
- 78207-120
- Amphenol FCI
-
1:
$3.13
-
699In Stock
|
Mouser Part No
649-78207-120
|
Amphenol FCI
|
Headers & Wire Housings LATCHING HDR 20 POSI
|
|
699In Stock
|
|
|
$3.13
|
|
|
$2.85
|
|
|
$2.70
|
|
|
$2.63
|
|
|
View
|
|
|
$2.51
|
|
|
$2.17
|
|
|
$2.12
|
|
|
$1.83
|
|
|
$1.62
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Shrouded
|
20 Position
|
2.54 mm (0.1 in)
|
2 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Wire-to-Board
|
|
- 40 C
|
+ 95 C
|
Bulk
|
|
|
|
Headers & Wire Housings B/S II SR RA
- 69191-206HLF
- Amphenol FCI
-
1:
$0.68
-
2,490In Stock
|
Mouser Part No
649-69191-206HLF
|
Amphenol FCI
|
Headers & Wire Housings B/S II SR RA
|
|
2,490In Stock
|
|
|
$0.68
|
|
|
$0.592
|
|
|
$0.542
|
|
|
$0.49
|
|
|
View
|
|
|
$0.447
|
|
|
$0.35
|
|
|
$0.288
|
|
Min.: 1
Mult.: 1
|
|
|
|
|
6 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings 12P VERT SR HDR AU
- 76384-312LF
- Amphenol FCI
-
1:
$1.97
-
699In Stock
|
Mouser Part No
649-76384-312LF
|
Amphenol FCI
|
Headers & Wire Housings 12P VERT SR HDR AU
|
|
699In Stock
|
|
|
$1.97
|
|
|
$1.86
|
|
|
$1.59
|
|
|
$1.22
|
|
|
View
|
|
|
$1.20
|
|
|
$1.17
|
|
|
$1.15
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Shrouded
|
12 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Straight
|
Pin (Male)
|
Gold
|
5 mm (0.197 in)
|
3.43 mm (0.135 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 40 C
|
+ 125 C
|
Tube
|
|
|
|
Headers & Wire Housings CRIMP - WIRE HOUSING SINGLE ROW 32 POS
- 65240-032LF
- Amphenol FCI
-
1:
$1.67
-
1,131In Stock
|
Mouser Part No
649-65240-032LF
|
Amphenol FCI
|
Headers & Wire Housings CRIMP - WIRE HOUSING SINGLE ROW 32 POS
|
|
1,131In Stock
|
|
|
$1.67
|
|
|
$1.42
|
|
|
$1.33
|
|
|
$1.27
|
|
|
View
|
|
|
$1.21
|
|
|
$1.13
|
|
|
$1.08
|
|
|
$1.03
|
|
|
$0.919
|
|
Min.: 1
Mult.: 1
|
|
|
Wire Housings
|
Receptacle Housing
|
32 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Cable Mount / Free Hanging
|
Crimp
|
Straight
|
|
|
|
|
BergStik
|
BergStik
|
Board-to-Board
|
30 AWG to 22 AWG
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings 26P DR HDR
- 69168-126HLF
- Amphenol FCI
-
1:
$2.17
-
551In Stock
|
Mouser Part No
649-69168-126HLF
|
Amphenol FCI
|
Headers & Wire Housings 26P DR HDR
|
|
551In Stock
|
|
|
$2.17
|
|
|
$2.09
|
|
|
$2.08
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Shrouded
|
26 Position
|
2.54 mm (0.1 in)
|
2 Row
|
|
Through Hole
|
Solder Pin
|
Straight
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.5 mm (0.138 in)
|
BergStik
|
BergStik
|
Wire-to-Board
|
|
- 40 C
|
+ 95 C
|
Bulk
|
|
|
|
Headers & Wire Housings 34P 2 ROW SMT HEADER VERT LOW PROFILE
- 72454-034LF
- Amphenol FCI
-
1:
$6.85
-
269In Stock
|
Mouser Part No
649-72454-034LF
|
Amphenol FCI
|
Headers & Wire Housings 34P 2 ROW SMT HEADER VERT LOW PROFILE
|
|
269In Stock
|
|
|
$6.85
|
|
|
$6.19
|
|
|
$5.85
|
|
|
$5.71
|
|
|
View
|
|
|
$5.42
|
|
|
$4.85
|
|
|
$3.92
|
|
|
$3.81
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Shrouded
|
34 Position
|
2.54 mm (0.1 in)
|
2 Row
|
2.54 mm (0.1 in)
|
SMD/SMT
|
Solder
|
Straight
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
|
BergStik
|
Quickie
|
Wire-to-Board
|
|
- 65 C
|
+ 125 C
|
Tray
|
|
|
|
Headers & Wire Housings BERGSTIK HDR DR RA-77317-114-12LF
- 77317-114-12LF
- Amphenol FCI
-
1:
$1.85
-
932In Stock
|
Mouser Part No
649-77317-114-12LF
|
Amphenol FCI
|
Headers & Wire Housings BERGSTIK HDR DR RA-77317-114-12LF
|
|
932In Stock
|
|
|
$1.85
|
|
|
$1.62
|
|
|
$1.55
|
|
|
$1.51
|
|
|
View
|
|
|
$1.44
|
|
|
$1.31
|
|
|
$1.20
|
|
|
$1.06
|
|
|
$0.887
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
12 Position
|
2.54 mm (0.1 in)
|
2 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
10 mm (0.394 in)
|
2.7 mm (0.106 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 130 C
|
Bulk
|
|
|
|
Headers & Wire Housings PV CARD CONNECTOR
- 68448-112LF
- Amphenol FCI
-
1:
$1.08
-
3,254In Stock
-
Factory Special Order
|
Mouser Part No
649-68448-112LF
Factory Special Order
|
Amphenol FCI
|
Headers & Wire Housings PV CARD CONNECTOR
|
|
3,254In Stock
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
2 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Straight
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.81 mm (0.15 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings BERGSTIK STACK HDR
- 54121-816102500LF
- Amphenol FCI
-
1:
$2.70
-
478In Stock
-
Factory Special Order
|
Mouser Part No
649-54121816102500LF
Factory Special Order
|
Amphenol FCI
|
Headers & Wire Housings BERGSTIK STACK HDR
|
|
478In Stock
|
|
|
$2.70
|
|
|
$2.47
|
|
|
View
|
|
|
$2.40
|
|
|
$1.97
|
|
|
$1.90
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
10 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Straight
|
|
Gold
|
8.79 mm (0.346 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
|
|
Bulk
|
|
|
|
Headers & Wire Housings LATCH HDR DR R/A
- 78207-108
- Amphenol FCI
-
1:
$1.78
-
947In Stock
|
Mouser Part No
649-78207-108
|
Amphenol FCI
|
Headers & Wire Housings LATCH HDR DR R/A
|
|
947In Stock
|
|
|
$1.78
|
|
|
$1.52
|
|
|
$1.20
|
|
Min.: 1
Mult.: 1
|
No
|
|
Headers
|
Shrouded
|
8 Position
|
2.54 mm (0.1 in)
|
2 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Wire-to-Board
|
|
- 40 C
|
+ 95 C
|
Bulk
|
|
|
|
Headers & Wire Housings FRICTION LATCH HDR DR R/A
- 78207-212
- Amphenol FCI
-
1:
$1.81
-
740In Stock
|
Mouser Part No
649-78207-212
|
Amphenol FCI
|
Headers & Wire Housings FRICTION LATCH HDR DR R/A
|
|
740In Stock
|
|
|
$1.81
|
|
|
$1.54
|
|
|
$1.10
|
|
Min.: 1
Mult.: 1
|
No
|
|
Headers
|
Shrouded
|
12 Position
|
2.54 mm (0.1 in)
|
2 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Wire-to-Board
|
|
- 40 C
|
+ 95 C
|
Bulk
|
|
|
|
Headers & Wire Housings PV
- 67030-001LF
- Amphenol FCI
-
1:
$0.23
-
7,000In Stock
-
Factory Special Order
|
Mouser Part No
649-67030-001LF
Factory Special Order
|
Amphenol FCI
|
Headers & Wire Housings PV
|
|
7,000In Stock
|
|
|
$0.23
|
|
|
$0.221
|
|
|
$0.192
|
|
|
$0.186
|
|
|
View
|
|
|
$0.178
|
|
|
$0.176
|
|
Min.: 1
Mult.: 1
|
|
|
Accessories
|
|
|
|
|
|
|
|
|
|
|
|
|
BergStik
|
BergStik
|
|
|
|
|
Bulk
|
|
|
|
Headers & Wire Housings BERGSTICK CONNECTOR
- 54201-G0802ALF
- Amphenol FCI
-
1:
$0.611
-
4,571In Stock
|
Mouser Part No
649-54201-G0802ALF
|
Amphenol FCI
|
Headers & Wire Housings BERGSTICK CONNECTOR
|
|
4,571In Stock
|
|
|
$0.611
|
|
|
$0.561
|
|
|
$0.559
|
|
|
$0.555
|
|
|
$0.497
|
|
|
View
|
|
|
$0.458
|
|
|
$0.434
|
|
|
$0.416
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Pin Strip
|
2 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder
|
Straight
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
Headers & Wire Housings 3P UNSHROUDED HEADER SMT VERTICAL
- 54201-G0803LF
- Amphenol FCI
-
1:
$0.761
-
6,109In Stock
|
Mouser Part No
649-54201-G0803LF
|
Amphenol FCI
|
Headers & Wire Housings 3P UNSHROUDED HEADER SMT VERTICAL
|
|
6,109In Stock
|
|
|
$0.761
|
|
|
$0.662
|
|
|
$0.654
|
|
|
$0.651
|
|
|
$0.621
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
3 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder
|
Straight
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings 2P UNSHROUDED HEADER RIGHT ANGLE
- 55101-T1102LF
- Amphenol FCI
-
1:
$0.211
-
19,192In Stock
|
Mouser Part No
649-55101-T1102LF
|
Amphenol FCI
|
Headers & Wire Housings 2P UNSHROUDED HEADER RIGHT ANGLE
|
|
19,192In Stock
|
|
|
$0.211
|
|
|
$0.181
|
|
|
$0.154
|
|
|
$0.136
|
|
|
View
|
|
|
$0.13
|
|
|
$0.116
|
|
|
$0.105
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Pin Strip
|
2 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Tin
|
5.84 mm (0.23 in)
|
2.29 mm (0.09 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings 1 POS I ROW HOUSING
- 65039-036LF
- Amphenol FCI
-
1:
$1.28
-
2,892In Stock
|
Mouser Part No
649-65039-036LF
|
Amphenol FCI
|
Headers & Wire Housings 1 POS I ROW HOUSING
|
|
2,892In Stock
|
|
|
$1.28
|
|
|
$1.13
|
|
|
$1.05
|
|
|
$0.897
|
|
|
View
|
|
|
$0.878
|
|
|
$0.873
|
|
Min.: 1
Mult.: 1
|
|
|
Wire Housings
|
Receptacle Housing
|
1 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Cable Mount / Free Hanging
|
Crimp
|
Straight
|
Socket (Female)
|
|
|
|
BergStik
|
BergStik
|
Wire-to-Board
|
36 AWG to 22 AWG
|
- 40 C
|
+ 105 C
|
Bulk
|
|
|
|
Headers & Wire Housings CRIMP - WIRE HOUSING SINGLE ROW 17 POS
- 65240-017LF
- Amphenol FCI
-
1:
$1.48
-
2,050In Stock
|
Mouser Part No
649-65240-017LF
|
Amphenol FCI
|
Headers & Wire Housings CRIMP - WIRE HOUSING SINGLE ROW 17 POS
|
|
2,050In Stock
|
|
|
$1.48
|
|
|
$1.26
|
|
|
$1.17
|
|
|
$1.12
|
|
|
View
|
|
|
$1.08
|
|
|
$0.986
|
|
|
$0.925
|
|
|
$0.85
|
|
|
$0.835
|
|
Min.: 1
Mult.: 1
|
|
|
Wire Housings
|
Receptacle Housing
|
17 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Cable Mount / Free Hanging
|
Crimp
|
Straight
|
|
|
|
|
BergStik
|
BergStik
|
Board-to-Board
|
30 AWG to 22 AWG
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings POLARIZATION PLUG PRICE PER EACH
- 65307-001LF
- Amphenol FCI
-
10:
$0.423
-
7,910In Stock
|
Mouser Part No
649-65307-001LF
|
Amphenol FCI
|
Headers & Wire Housings POLARIZATION PLUG PRICE PER EACH
|
|
7,910In Stock
|
|
|
$0.423
|
|
|
$0.404
|
|
|
$0.393
|
|
|
$0.37
|
|
|
View
|
|
|
$0.352
|
|
|
$0.326
|
|
Min.: 10
Mult.: 10
|
|
|
Accessories
|
|
|
2.54 mm (0.1 in)
|
|
|
|
|
|
|
|
|
|
BergStik
|
BergStik
|
Wire-to-Board
|
|
- 40 C
|
+ 105 C
|
Bulk
|
|
|
|
Headers & Wire Housings 12P SR UNSHRD HRD .76 GOLD OVER NI
- 68016-112HLF
- Amphenol FCI
-
1:
$1.15
-
4,677In Stock
|
Mouser Part No
649-68016-112HLF
|
Amphenol FCI
|
Headers & Wire Housings 12P SR UNSHRD HRD .76 GOLD OVER NI
|
|
4,677In Stock
|
|
|
$1.15
|
|
|
$0.832
|
|
|
$0.801
|
|
|
$0.785
|
|
|
View
|
|
|
$0.755
|
|
|
$0.745
|
|
|
$0.633
|
|
|
$0.599
|
|
|
$0.537
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
12 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings 4P SR UNSHRD HRD .38 GOLD OVER NI
- 68016-204HLF
- Amphenol FCI
-
1:
$0.34
-
8,763In Stock
|
Mouser Part No
649-68016-204HLF
|
Amphenol FCI
|
Headers & Wire Housings 4P SR UNSHRD HRD .38 GOLD OVER NI
|
|
8,763In Stock
|
|
|
$0.34
|
|
|
$0.286
|
|
|
$0.258
|
|
|
$0.241
|
|
|
View
|
|
|
$0.213
|
|
|
$0.202
|
|
|
$0.201
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
4 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Gold
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings 3POS R/A HDR SnPb
- 68016-403HLF
- Amphenol FCI
-
1:
$0.27
-
14,691In Stock
|
Mouser Part No
649-68016-403HLF
|
Amphenol FCI
|
Headers & Wire Housings 3POS R/A HDR SnPb
|
|
14,691In Stock
|
|
|
$0.27
|
|
|
$0.245
|
|
|
$0.191
|
|
|
$0.173
|
|
|
View
|
|
|
$0.154
|
|
|
$0.142
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
3 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Tin
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
|
|
Headers & Wire Housings 4POS R/A HDR SnPb
- 68016-404HLF
- Amphenol FCI
-
1:
$0.20
-
20,531In Stock
|
Mouser Part No
649-68016-404HLF
|
Amphenol FCI
|
Headers & Wire Housings 4POS R/A HDR SnPb
|
|
20,531In Stock
|
|
|
$0.20
|
|
|
$0.177
|
|
|
$0.166
|
|
|
$0.152
|
|
|
View
|
|
|
$0.14
|
|
|
$0.127
|
|
|
$0.12
|
|
|
$0.116
|
|
Min.: 1
Mult.: 1
|
|
|
Headers
|
Unshrouded
|
4 Position
|
2.54 mm (0.1 in)
|
1 Row
|
|
Through Hole
|
Solder Pin
|
Right Angle
|
Pin (Male)
|
Tin
|
5.84 mm (0.23 in)
|
3.05 mm (0.12 in)
|
BergStik
|
BergStik
|
Board-to-Board
|
|
- 65 C
|
+ 125 C
|
Bulk
|
|
South Africa