SHD TTB Series - Swivel Heavy Duty Castor Wheels are specially designed with a brass frame and polyurethane material. These are flame retardant and water proof. These wheels are useful in different applications. SHD TTB Series - Swivel Heavy Duty Castor Wheels are easy to fixed and remove without any worry. These are silently run with no noise and scratching the floor. These are helpful to move the objects in a smoother manner.