Feature:1. With standard inner and outer diameter size, it is convenient to install and disassemble.2. There are no cracks or pores on the surface of these piston rings, and good air tightness can be ensured when connecting.3. The function of the piston ring is to maintain the air tightness between the piston and the cylinder wall.4. The kit contains 3 replacement piston rings, which can replace the old or damaged ones on the air pump at any time.5. Suitable for air compressors and air pumps with a cylinder diameter of 47mm, and need to be replaced when the axial clearance is greater than 0.13mmSpecification:Item Type: Piston Ring KitModel: 47 Piston RingDrive Mode: PneumaticPiston Ring Outer Diameter: Approx. 50mm / 2inPiston Ring Inner Diameter: Approx. 44mm / 1.7inApplicable Models: Approx. 47mm / 1.9in cylinder diameter for Outstanding/Jaguar 1P/2.5P/3P/4P air compressor air pump accessories.Package List:3 x Piston RingNote:The number 47 means that the cylinder diameter is 47mm.