Wide Compatibility RangeThe four-way coil spring compressor can make your installation easier and faster. Bent leg repairs, leg tube repairs and damaged parts only; Quickly and safely compress the strut spring for easy replacement of the strut cartridge or repair of the strut and strut assembly Safety and durabilityThe wide hook and bolts are made of 40CR steel, more durable and durable, small pins which prevent the compressor from flying off the coil spring. Locks it onto the spring so it can't come free until you pull it back. Groove tool will last for years. Wide ExtensionUniversal for small, medium and thicker coil springs. But there is always the size range. Please check it carefully before purchasing. (1) Maximum spring diameter: 12/20 cm; (2) Maximum length of the compressible spring: 25.4 cm (3) Maximum outer diameter of the strut spring: 15 cm Use a ratchet Alternately tightening each socket wrench 3 or 4 turns, compress the spring evenly and ensure tools do not slip or move on the spools. You can use a 7/8" socket. No instructions included.