This is the vented 1/8th scale clutch bell from UR. This bell has been designed with three irregular holes to allow air to help cool the clutch bell and clutch shoes for longer life, as well as allow debris to leave the clutch bell for smoother operation. It includes 2 bearings. This clutch bell works great with the UR Compak Clutch System. Available in 13, 14, 15, 16 and 17 tooth.