Made of durable materials, these piston rings are longlasting. Maintain tightness: The piston rings help maintain a tight seal between the piston and cylinder walls. Easy installation: With standard inner and outer diameters, installation and removal are easy. No casting defects: The rings are from cracks, pores, or looseness, ensuring a tight connection. Replacement kit: Includes 3 piston rings for replacement of worn or damaged rings on the pump. Wide compatibility: Suitable for compressors and pumps with a cylinder diameter of 55 mm; when axial clearance exceeds 13 mm. Use scenarios Routine maintenance of a 55 mm cylinder air compressor showing reduced sealing or performance can be addressed by replacing with this kit to restore compression. During a pump overhaul where cylinder wear has increased axial clearance, the rings to reestablish proper clearance and sealing. In field service for 55 mm cylinder equipment, keep this 3ring kit on hand for timely replacement when axial clearance exceeds 13 mm.