Features:* replacement piston, suitable for piston air compressor pistons and air pump pistons.* The whole machine has simple and compact structure, light and flexible movement.* , anti-corrosion, impact resistant, anti-oxidation, high temperature resistant, wear resistance.* The function of the piston ring is to maintain the tightness between the piston and the cylinder wall.* With the standard size of inner and outer diameter, it is convenient to install and dismantle.* The surface has no casting defects such as cracks, pores, clearance, etc., ensuring a tight connection.* The kit includes 1 piston + 3 spare piston rings (including 2 pcs. Balance ring + 1 pc. O-ring), which can replace the old or damaged ones on the air pump at any time. Specifications:* Item Type: Air Compressor Piston + Piston Ring * Material: Metal * Color: Silver, Black * Suitable Cylinder Diameter: 42mm 47mm 48mm 51mm 65mm, please choose the right size.* Bore Diameter: As the picture shown * Application: Air Compressor Piston Type, Air Pump Piston * Quantity: 4pcsPackage Contents:1 x Air Compressor Piston3 x Air Compressor Piston RingsNote:1. The actual colors of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.2. Please allow slight manual measurement deviation for the data.