These casters feature the extra soft (60 Durometer) solid rubber
"Super Flex" wheels that resemble pneumatics in appearance, but being
puncture proof eliminate the risks of flats.
The extra thick rubber tires are permanently vulcanized to cast aluminum rims
with roller bearings.
For use over very rough surfaces like steel grating, door sills, etc., or to provide greater
cushioning than is achievable with other wheel types.