Never-Flat (NF) Recommended for the greatest possible protection to both loads and floors. Perfect replacement tire for pneumatic or semi-pneumatic applications. This solid urethane tire has similar rollability characteristics as a pneumatic tire... but they never go flat. Optional colors and caster configurations, consult factory. Replacement parts available. 8" Grey wheel. 10" Black wheel. Heavy duty 350 pound load capacity! Looks and performs similar to pneumatic wheels, but without the hassles of air pressure maintenance and flat tire repair. Reduces maintenance time and expense. Closed cell expanded foam construction resists water absorption (unlike others currently in the marketplace). Sawtooth tread for easy maneuverability and traction (radial tread on 8??? model). Quiet, smooth operation. Non-marking for superior floor protection. Rolls over obstacles with ease and absorbs shock to protect cargo. Zerk fittings.