Product Features: 1. Every product has a unique Manufacturing Part Number label on the inner package that proves it has been qualified, which includes Part Number, Model Number, and inspection date information. 2. If you have any questions about the item, please provide the Manufacturing Part Number for verification. 3. The piston set for air compressor 42 is made of metal. Piston diameter: 42mm, height: 36mm, aperture: 12mm, piston ring oil ring thickness: 3mm, gas ring thickness: 2mm, piston pin length: 34mm, diameter: 12mm, circlip: 13mm. 4. Suitable for air compressors. 5. Accessories include: 1 x piston, 1 x piston oil ring, 2 x gas rings, 1 x piston pin, and 2 x circlips. Specifications: Product Material: Metal Color: Silver and Black Name: BQLZR Size: 4.2 x 3.6cm / 1.65 x 1.42 inches (D x H) Piston Diameter: 42mm, Height: 36mm, Aperture: 12mm, Piston Ring Oil Ring Thickness: 3mm, Gas Ring Thickness: 2mm, Piston Pin Length: 34mm, Diameter: 12mm, Circlip: 13mm Weight: 83g Package Includes: 1 x Piston 1 x Piston Oil Ring 2 x Gas Rings 1 x Piston Pin 2 x Circlips Note: Due to differences in monitor models and display settings, there may be slight variations in color. Size measurements are manually taken and may have an error of 1–2cm.