Double click to engage properly.First click locks coupler and plug.The second click engages the air pressure.To disconnect push button twice. First push relieves pressure and second push allows plug and coupler to be disengaged.Please check new product details The profile is for 7.4 mm Europe plug, which comforms with ROHS, CE.double click safety coupling pneumatic safety coupling Meanwhile, we also have milton and PLC profile, please check the  5.5mm pneumatic push button coupling profilenylon push button coupoling   XHnotion produce thousands of air coupling models, below is corresponding list.Pneumatic quick-disconnect couplers profile