Tired of gas leaking out of the fill-valve when you are charging it? Apply these o-rings to your gas magazines and they will fill like never before. Replace blown out or worn out o-rings on gas gun magazines, grenades, and shells with this quality upgrade product. Meets or exceeds original equipment specifications. For WE, KJW, KWA, HFC, Bell, Tanaka, Marushin, Maruzen, WELL, Snowwolf and other compatible models. *May not work on certain TM models due to tiny valve.