One-time molding, a hard protective layer is produced on the surface, which is anti-oxidation, wear-resistant and durable, and improves the service life of the product Hard oxidation treatment, with super anti-oxidation ability, not easy to aging The material is thicker, which improves the stability of the cylinder and has stronger impact resistance Imported sealing ring + thickened cylinder body, smooth for a long time without jamming, air leakage, wear-resistant and dust-proof, Manufacturer: OTENC