Littelfuse Fuse Products Traditional Part Numbering System

Product Series Code

Example: 437 series fuse is “0437”

Ampere Rating Code

Decimal is to far right for whole number amp ratings, to far left for ratings less than one, and within center for fractional amp ratings.

Examples: 10A fuse is “010.” 1/4A or 0.25A fuse is “.250” 1 1/2A or 1.5A fuse is   “01.5” 1 1/4A or 1.25A fuse is “1.25”

Packaging Type *   

A Ammo packed B Bubble packed C Chip packed R Reeled X Filler

Packaging Quantity Code *

A/X 1 V 5 T 10 S 20 L 50 H 100 F 200 G 250 U 500 M 1000 D 1500 P 2000 E 2500 W 3000 Y 4000 N 5000 K 10000 J 12000 Z Misc.

Options Codes *

RT1 Reel and Tape, 2.062in (52.4mm) lead spacing RT2 Reel and Tape, 2.50 in (63.5mm) lead spacing RT3 Reel and Tape, 2.874 in (73mm) lead spacing E Pigtail lead type fuse ID Indicating fuse L RoHS compliant P Lead-free