The Strongway 6in. Swivel Flat-Free Rubber Foam-Filled Caster keeps your equipment rolling over the toughest conditions, eliminating costly and inconvenient flat tires. Smooth-rolling tire moves easily and provides improved traction without marking floors. Wide tire design provides stability on rough surfaces. Steel frame has double ball bearings and bright zinc electro-galvanized finish for rust prevention. Ideal for low speed uses on all indoor and outdoor surfaces.