Snap Serts are a time-saving installation and release system for molded-in inserts. They are manufactured in an all stainless steel single detent ball construction. They fit most common thread sizes. Due to variation in inserts, you may wish to send a sample insert with your order for proper fitting. (Your Insert thread size: 5/16-18, Norstar's "Snap Sert" thread size: 1/4-20). Stationary Snap Sert includes washer, pin, and nut.