Comes with two pieces ,the outer diameter is 24mm and inner diameter is 18mm. fit most of brand 110 125 150 250 300 800 1100cc go kart like SUNL, TAOTAO, COOLSTER ,BMS, BMI, NST, DAZON, YONGHE, AMERICAN SPORTWORKS, TRAIL MASTER.
It is the No 4 or No 12 parts in the parts breakdown .