Bostitch BTFP72321 Universal 1/4-Inch Series Coupler Push-To-Connect with 1/4-Inch NPT Female Thread Accepts 1/4" series Industrial interchange, 1/4" Automotive interchange, or ARO interchange plugs Pre-applied thread sealant for airtight connections Simplifies field installation by eliminating the need for thread sealant tape Plated steel construction with drag guard for jobsite durability and reliability 6-ball coupler design for balanced, strong, secure connections