Master Mechanic, 1/4" Female Safety Coupler, 1/4" I/M Coupler - 1/4" NPT Female, 2 Stage Release Mechanism Prevents Injury Or Damage That Could Result From Accidental Disconnects, Push Once To Stop Air Flow, Twice To Release Plug, Unique Push Button Design Allows For Fast & Easy Connection & Disconnection Of Tools While Eliminating Air Pressure & Air Blow Back.