this trolley I designed to roll on para-cord is good for 200lbs rated so far need ,two side plates ,two pulleys printing stopped at 80% to insert two .625" OD x 1/4" id x.1875 width ball bearings. I printed the "knobs" called grip.stl file someone else made for the 1/4" hex head screws for quick detachment of the trolley also need 3- 1/4" x 2" hex head cap screws and nuts with 14 small 1.4" washers as spacers