CMI® Velocity Micro Trolley Pulley (Microtrolley) is a smaller version of the Heavy Duty Trolleys made by CMI. This high quality trolley will work on up to 1/2" rope and cable. It features two 1-1/2" stainless steel sheaves that are on ball bearing along with a stainless steel axle. Microtrolley58 will work on up to 5/8" rope and cable.