Withstand Heavy: the 4 wheel trolley measures about 9/16 inch/ 14 mm in diameter, 2/5 inch/ 10 mm in thickness, which is suitable for 1-5/8 inch wide strut channels; And each of the trolley can load about 800 lbs, 1600 lbs for 2 Material: the channel trolley and channel trolley hanger are mainly made of reinforced solid steel, and with galvanizing performance, sturdy and , not easy to deform or rust, which can you for a long time Flexible Running Direction: the electric hoist roller trolley can be applied to the supporting channel, and it is provided with two moving directions, so that the can work in different positions and transport Combination: the package comes with 2 pieces of trolley intermediate support hangers and 2 pieces of roller , 4 pieces in , which are good combinations for assembling trolley to work Safe for Use: the hoist trolley is welded and pin of roller, which provides greater stability for safe use; It uses deep groove to that you can operate smoothly without making any noise. Material: steel colour: silvery Package Contents: 2 x Electric Hoist Installation Roller 2 x Trolley Support Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.