Made of high quality stainless steel, oxidation resistant and rust resistant, increase the life Good fittings and high performance Good quality fittings and worked for the application. Effectively prevent from happening Widely used for connecting bowden extruder Easy to connect by inserting the tube and it will automatically lock tight Easy to disconnect tube by one push on the black cap PC4-M10: the upper part can be inserted 4MM diameter tube and self-locking, the following thread were M10 and 1 points (about 9.6MM Tubing OD: 4mm Thread:6mm Color:silver Material:Stainless steel Package Contents: 10 * male straight pneumatic connector Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.