Amazon.com: uxcell Push to Connect Fittings, Cap Style Pneumatic Blanking Plugs, Fit for 6mm Inner Dia. Air Hose Tube Pipe, Plastic, Black, Pack of 20 : Industrial & Scientific
1/4 in. Fittings Male Pneumatic Plug - AndyMark, Inc
10mm x 3/8'' Push-in Fitting with Plug-in PA 66 NBR [2 Pieces] | Tameson.com
Threaded Straight Through Pneumatic PU Air Pipe Quick Plug Solenoid Valve Connector – Inosaki