HEAVY DUTY MATERIAL - The groove wheel is made of high quality 304 stainless steel, corrosion-resistant, rigid strong, and durable to use. 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. DETAIL SPECIFICATIONS - V 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. WIDELY APPLICATION - The sliding gate rollers can be used for heavy-duty sliding gates, inverted tracks, yard gates, rolling shutters, industrial machines, wire rope rails, garage gate, dog gate etc. The slide gate wheel smooth as silk.