A multi-purpose and adjustable pulley system that attaches to the back of your rack allowing you to do seated rows, lat pulldowns, biceps curls amongst a host of other pulling based exercises. Includes a lat pulldown bar attachment and a short bar attachment and leg holder. Fits the Residential Rack 4.1 and light commercial power rack 5.1 Like new, selling because I bought the wrong one for my rack and it's past the return window. Only been opened and partially assembled before I realized my mistake. All parts accounted for, manual included.