The v-style bracket is manufactured via one time stamping technique which makes it more stable. STAINLESS STEEL MATERIAL: The groove wheels are made of stainless steel which have higher strength, super capability, anti-deformation and corrosion resistant. STRONG LOAD CAPACITY: The thickened steel plate bracket and wheel core can enhance the bearing capacity, and the load capacity of every 2inch caster wheels is up to 500lbs. SIZE SPECIFICATIONS: Wheel diameter: 4.8cm /1.89inch, Slot width: 1.6cm/0.63in, Groove depth: 0.7cm/0.28in. MUTE DUPLEX BEARINGS: There are two rolling bearings built in the groove wheel, which can reduce the friction with the wheel and ensure quiet and smoothy rolling. WIDE APPLICATION: The track rollers can be used for inverted track, sliding gate, rolling shutters, industrial machines, wire rope rails, container shelves, garage gate, etc.