These spring loaded hand retractable plungers have a wide range of applications to lock items in place. They are used to prevent any change in position due to lateral force. Pulling up on the D-ring retracts the plunger pin completely into the body and unlocks the mechanism. D-ring made from 300-series stainless steel uncoated. Body and plunger pin made from AISI-4140 alloy steel with a black oxide finish. Spring made from 17-7 stainless steel.