Quantity: 4. Steel construction with rubber tires. Each wheel is approx 2 1/2″ from side to side. The tire is approx 7/8″ wide. Caster is approx 4″ tall from base to bottom of wheel. Ball bearing swivel design. Top plate is approx 2 5/8″ long x 2 1/8″ wide. 4 adjustable mounting holes. Brake to lock the caster in place.