materials and build: The leg extension and curl attachment is crafted from heavy duty steel to ensure a sturdy, stable construction with a load capacity of up to 600 pounds, capable of withstanding demanding leg training. Rack compatibility and mounting: Designed to be mounted on a power rack, it fits racks with holes of 1.6 cm, 1.8 cm, or 2.6 cm (0.6, 0.7, 1 inch). It is applicable to barbell plates with a diameter of 2.5 cm (1 inch) or 5 cm (1.97 inches). Make sure your fitness rack has penetrable holes before . Eight adjustable positions: The seated leg extension and curl machine offers 8 adjustable positions to suit body size and training requirements during muscle group training. Ideal for strengthening triceps, biceps, chest, shoulder and back muscles. Seated leg extension and curl machine design: This leg curl and extension rack attachment breaks the traditional bench leg extension design. It is detachable, adjustable, easy to store, with a small size and light weight. It can effectively train your leg muscle groups without taking up much space. Includes mounting screws and bolts for easy installation. Use scenarios and applications: Home gym with a standard power rack: quickly attach the unit to perform seated leg extensions and curls, maximizing existing rack use and saving space. Shared or multiuser facility: detachable design and simple mounting allow fast setup and teardown, accommodating different users with minimal equipment swapping. Progressive training setups: the 8position adjustment and compatibility with various plate diameters enable customized resistance and varied leg workout routines within a compact footprint.