1. HIGH QUALITY MATERIALS The leg curl extension machine is carefully crafted from durable steel materials to ensure a sturdy construction weighing up to 600 pounds and a sturdy construction with high load capacity that can withstand demanding leg training. 2. FIT SQUAT RACK HOLES The leg extension should be mounted on a power rack for training and fits racks with 0.6/0.7/1' holes and applicable to barbell plates with a diameter of 1' or 2' (5cm). Make sure you have a fitness rack with penetrating holes before you buy this product. 3. 8 GEARS ADJUSTABLE The leg extension and curl machine while sitting allows the user to adjust to the height and training requirements during muscle group training. The leg extension attachment features 8 adjustable positions to ensure a fit for each individual. Ideal for strengthening triceps, biceps, chest, shoulder and back muscles. 4. Sitting Leg Extender Curl Machine This leg curl and extension rack attachment breaks the traditional design of bench leg extension. Removable, adjustable, easy to store, small and lightweight. Able to effectively train your leg muscle groups without taking up too much space for you. Includes mounting screws and bolts for easy installation.