Zinc plated swivel/brake castor with bolt hole bracket made of pressed steel with double row ball race in swivel head.Foot operated brake that locks both swivel and wheel simultaneously.Wheel with blue elastic rubber vulcanized on nylon centre. Hardness of tread 70° shore A.Bolted wheel axle.Low rolling resistance and operation noise. Very good floor preservation.The elasticity of the rubber makes the wheel resume to its round shape faster, avoiding flat spots, and therefore gives a lower rolling resistance than for standard grade rubber.Good chemical resistance, except to oils.