Premier B pulser, optical encoder, also know as 421031-021

black long shaft, replaces part number 421031-9 / 421031-009

Bourns ENZ1D-495-L00100L

also a Gasboy part number 13078

It's item 23 in the line drawing

Doc Boehme
Bottom Line of MN
Providing gas pump repair parts since 1993
(763) 300-2298