If you have a SILCA PISTA made since 1946, a SUPERPISTA since 1989, or any of the Impero Frame Pumps since 2015, it has a check valve assembly like this to ensure that air can only go in one direction.

Features
Kit contains Brass Plunger, O-ring, Stainless Steel Spring and Aluminum Crush Washer
Made in Italy and USA
Allows airflow only in one direction

Mfr Claimed Weight
TBC