Carter WCFB Accelerator pump plunger 5/8" Dia. 

Carter WCFB, 4 barrel carburetor accelerator pump. 5/8" cup x 2.040 overall length. Leather cup 

As used in these carbs:

2556S, 2556SA, 2656s, 2656SA, 2657s, 2657SA, 2669s, 2669SA, 2816S, 2816SA, 2817S, 2817SA, 2818S,
2818SA, 2829s 2830s 2831s, 3059S, 3059SA, 3060S, 3060SA, 3061S, 3061SA, 3165s 3166s 3167s 3190s,
3190SA, 3191s, 3191SA, 3205s, 3205SA, 3419s 3420s 3422s 3423s, 3489S, 3489SA, 3500s, 3500SA, 3501s,
3501SA, 3575s 3696s, 3696SA, 3697S, 3697SA