Grey type push in fitting, pneumatic fitting, push to connect fitting internal hexagon male straight connector with round body and internal hexagon is widely used in the application where the assembly space is limited. In line connection of tubing to a female threaded port. Pre-coated threads are ready to use without additional sealing. Push in fitting, pneumatic fitting, push to connect fitting hexagon socket head male straight connector is made of nickel plated brass and has grey color POM release button, stainless steel tube gripping claw. Pre-coated Teflon threads are ready to use without additional sealing. Push in pneumatic fittings are easy to install and release. Simple installation–push the tubing in, and the connection is complete. To release the tubing, press the release sleeve on the fitting, and you can easily pull the tube out. Internal adjustment with an Allen wrench. Accommodate metric tubing O.D ranging from 4 mm to 16 mm, inch tubing O.D ranging from 1/8″ to 1/2″.Thread sizes range from R, PT, BSPT 1/8 to R, PT, BSPT 1/2.