QuickConnector is a stainless fitting with a silicone grip and a silicone o-ring. The straight barbtail piece is compatible with some types of 3/8" (9.5 mm) push-in-couplings, but not John Guest.
Easily connected without tools.
Stem for tubing or coupling: 9.5 mm, compatible with 3/8" push-in (not John Guest)
Internal threads: 1/2" NPT (American pipe thread)
Material: Stainless Steel and Silicone