Carter W-1 Rebuild Kit   long FLAT SHAFT PLUNGER type

As used in:

Chevrolet 1941-52 with Carb nos.  684S, 684SA, 839500; 3688154

Check the length of the plunger in your carb if you are not sure of carb number.

Kit includes Idle Jet, Economiser Jet, all clips, copper washers, check valve, pump plunger & Needle & Seat

Pump Plunger in this kit is flat shaft type, 2.645” [67.2mm] O/all length with cup of 3/4” [19.05mm] diameter.

Check your requirements carefully.
Another kit to suit W-1 Carter carbs fitted to these Chevs is CK4063 
That kit has a shorter FLAT SHAFT pump plunger @ 2.5” [63.5mm]