This 4-piece DIA Accessory Set includes a 4" diameter wheel, a 4" diameter base, a 4" diameter arm, and a 4" diameter handle. The wheel and base are made of durable, heavy-gauge steel, and the arm and handle are made of high-quality plastic. This Accessory Set is perfect for use with the DIA 4" diameter Accessory Wheel and Base. This 4-piece DIA Accessory Set includes a 4" diameter wheel, a 4" diameter base, a 4" diameter arm, and a 4" diameter handle. The wheel and base are made of durable, heavy-gauge steel, and the arm and handle are made of high-quality plastic. This Accessory Set is perfect for use with the DIA 4" diameter Accessory Wheel and Base.