Pneumatic fittings are used in pneumatic piping. The tube fittings come in a wide variety of models to meet all your needs in pneumatic piping. Even after installation, the direction of the tube can be changed freely Nickel-palted metal body ensures anti-corrosion and anti-contamination. All R and NPT threads are pre-coated sealant. Features: 1) Suitable for any tubes. 2) Easy steps to take tubes off. 3) Once inserted to the nut, the tube would not easily loose 4) Nickel-plated metal body ensures anti-corrosion and anti-contamination 5) All R and NPT threads are pre-coated sealant 6) Quick and simple tube insertion 7) Compact, lightweight design 8) Advanced, well-proven tube retaining system 9) Re-usable thread seal