Model 2-50 Swivel and Rigid Dual wheel swivel casters are industrial plate casters.  They have two non-marking wheels which protect the floors by spreading the load over a larger area.  Dual wheel casters provide a minimum overall height with a higher load capacity than a caster with a single wheel.  The wider footprint provided by two wheels enables dual wheel casters to cross over gaps and grooves in the floor more easily than a narrow single wheel.