Feature:1. High quality material can make sure the durability and stability of the product, with good sealing2. When the axial clearance of the gas ring is greater than 0.13mm, it is recommended to replace the piston ring3. Professional design and reasonable structure, easy to install and disassemble4. The piston ring is suitable for 90mm cylinder diameter, standard workmanship, simple to replace5. Suitable for cylinders with a cylinder diameter of 90mm, 4KW 7.5KW motor, 0.6/8 0.9/8 air compressor, air pump, etc.Specification:Item Type: Piston RingModel: 90 Piston RingDrive Mode: PneumaticPiston Ring Outer Diameter: Approx.95mm / 3.7inPiston Ring Inner Diameter: Approx. 85mm / 3.3inCylinder Diameter: Approx. 90mm / 3.5inApplicable Models: Cylinder diameter 90mm, cylinder 90 mm, etc. 4KW 7.5KW motor, 0.6/8 0.9/8 air compressor air pump accessoriesExplanation: [90 Piston Ring] The number "90" means that the cylinder diameter is 90mm .Package List:3 x Piston Ring