Use compressor to install pistons 53 to 125mm in diameter. Positive lock action provides positive compression and fingertip release. To compress piston ring into grooves, slip the tool over the piston and tighten with L-shaped wrench. Insert piston into cylinder and tap with a hammer to install. Enlarged crimped edge prevents compressor from entering the cylinder. Product Name : Piston Ring Compressor Material : Metal Capacity : 53-125mm / 2.1-4.9 inch Compressor Height : 7.5cm / 3inch Wrench Size : 9 x 8.8 x 0.5cm / 3.5 x 3.4 x 0.2 inch (L*W*T) Color : Silver+ Black blue Net Weight : 232g Package Content : 1 x Piston Ring Compressor 1 x L Shaped Wrench Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.