This is a bellows rebuild kit for old-style Walbro WEP fuel pumps.

What follows is some background/reference information:
Old-style Walbro WEP reciprocating fuel pumps were extremely popular as supply pumps for diesel cooking and heating stoves and their associated "day" tanks on vessels of all types.

As time passes, fewer replacement/repair parts are available for these pumps.
Refer to the new Walbro FRD pumps which have replaced the WEP series.

Model WEP-12 (#2401-1) was the standard pressure model - 4.5 to 7.0 PSI output
Model WEP-13 (#2402-1) was the low pressure model - 2.5 to 4.0 PSI output
Model WEP-38 (#2403-1) was the adjustable pressure model - 1.75 to 6.0 PSI output