Two 2" or 3" non-marking gray soft rubber ball bearing wheels.
Soft rubber wheels provide a cushioned resilient ride protecting cargo as well as floor surfaces. It also reduces noise, vibration and rolls over small obstructions. Polyurethane wheels provide quiet rolling with a higher capacity.
The wider footprint provided by two wheels enables the casters to cross winch tracks, gaps and grooves in the floor.
Dual Wheel casters provide a higher load capacity with a minimum overall height.
The differential action provided by two wheels enables the caster to swivel easier than a single wheel having the same size footprint.
The Total Locking Brake locks both the swivel and the wheel simultaneously.
If these casters are going to be left parked for a prolong period there is the possibility that the tires could develop a flat spot. As a general rule, in situations like this reduce the rated capacity by 50% in order to minimize the possibility of a flat spot.