The Marcy Pro PM-30 arm curl is an accessory that adapts to the Marcy Pro PM 3800 Power Rack + Bench. The arm curl accessory places the upper arm in the correct position, allowing the lever handle to isolate the bicep muscles which eliminates the potential for improper form throughout the range of motion. Dual pivot points on the bicep handle ensures that every rep is smooth and precise. Backed by a manufacturer"s 2 year limited warranty.