Feature:1. There are no cracks or pores on the surface of these piston rings, and good air tightness can be ensured when connecting.2. Contains 3 piston ring replacement parts, you can replace the old or damaged on the air pump at any time.3. Suitable for air compressors with a bore of 42mm, and suitable for Outstanding/Jaguar air compressors.4. The inner and outer diameters of the piston ring are standard, and it is easy to install and disassemble.5. When the axial clearance of the gas ring is greater than 0.13mm, it is recommended to replace the piston ring.Specification:Item Type: Piston RingModel: 42 Piston RingDrive Mode: PneumaticPiston Ring Outer Diameter: Approx. 44mm / 1.7inPiston Ring Inner Diameter: Approx. 40mm / 1.6inApplicable Models: Approx. 42mm / 1.7in cylinder diameter for Outstanding/Jaguar 1P/2.5P air compressor air pump accessories.Package List:3 x Piston RingNote:The number 42 means that the cylinder diameter is 42mm.