Phenolic caster wheels are made from heavy weave canvas duck, impregnated with phenolic resin, and molded under high pressure and temperature. Its hardness is comparable to polished maple flooring. Phenolic caster wheels are recommended for smooth concrete or wood floors, and can be used for storage (standing) loads without permanent set. These caster wheels are highly resistant to oil, grease, water, mild acids, and animal fat. They are affected in various degrees by strong acids and some alkaline solutions. Temperature range is -40°C to +260°C , with intermittent use up to 300°C . Phenolic castor wheels will carry loads as great as the same size iron wheel. The wheel material may chip or cut from contact with steel plate or from rolling over steel parts on the floor. The wheel tread may show wear from repeated travel over rough surfaces. Phenolic caster wheels are best for loads beyond the capacity of the same size rubber wheel. Floor wear is slight except where floors are already starting to deteriorate.