Smooth Rolling: Each wheel uses double 6000RS steel sealed ball bearings for resistance and durability. The vgroove wheels operate on an inverted vtrack, reducing rolling friction and making heavy rolling tasks easier. Strong Load Capacity: Each heavy duty caster has load capacity, and all four casters together can carry up to 2200 lbs. Material and Construction: Standard 45 steel with galvanized finish. Bracket thickness is 11 gauge (3 mm). These vgroove wheels are precisely machined, delivering a solid construction with consistent quality and very smooth rolling resistance. Applications: Fit to inverted 90degree angle vtrack; heavyduty rolling door; sliding gate; industrial machines wire rope device; containers racks; sawmill; dog fence and more. Use Scenarios: Replacing casters on a large rolling door in a warehouse to improve movement and reduce effort. Installing on a sliding gate or industrial access barrier to handle loads with smooth operation. Mounting on heavy equipment racks or sawmill tooling to enable easy movement of heavy components.