Features:Suitable piston inner diameter: 46-48.5mm /1.81-1.9 inch; outer diameter: 49-52.5mm /1.92-2.06 inch. Three sets of high-quality Air Compressor piston rings The main job of the piston ring is to seal the combustion chamber on the piston housing and transfer heat from the piston to the cylinder. Made of metal material, good texture, strong and stable, not easy to damage .Provide better sealing, improve performance, and reduce fuel consumption. Note: When replacing the piston ring, please turn off the air compressor and release the pressure. Package Includes:3 Pcs Air Compressor Piston Ring Specifications:Material: MetalColor : BlackSize: Approx. Inner Diameter : 46-48.5mm /1.81-1.9 inch Approx. Outer Diameter : 49-52.5mm /1.92-2.06 inch. note:1.Please allow 1-2mm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.