Fuperoo Wheel Trolley Assembly rollers。 There are multiple styles to choose from. The material adopts low-speed load-bearing bearings and galvanized steel plates, which are durable and long-lasting. Widely applicable, it can be used for sliding doors, electric hoists, small elevators, high-altitude slides and some amusement facilities, heavy curtains, handmade crafts, heavy object movement and suspension, etc. for use with 1-5/8" Wide and All 1-5/8" or Taller Strut Channel.