Stainless Steel Material: The groove wheel is made of high quality stainless steel, solid and durable to use. Detail Specifications: U Type Pulley Block. Wheel Diameter 6.8cm/2.68in, Groove Width 2.2cm/0.87in, Groove Depth 1.3cm/0.51in. Strong Load Capacity: The thickened steel plate bracket and wheel core can enhance the bearing capacity, and the load capacity of every 3inch caster wheels is up to 880lbs. Double Roll Bearings: Each groove wheel is quipped with double roll bearings, which can reduce the friction with the wheel, making it easy to push the gate. Wide Application: The track rollers can be widely used for heavy duty sliding gates,inverted tracks,rolling shutters,industrial machines,wire rope rails,garage gate etc. The smooth rolling operation of the grooved wheel enables effortless gate movement, reducing friction and strain on the gate operator.