Chinese sealed bearings, front 6205-2Z OD 52mm ID 25mm and rear 6005-2Z OD 47mm ID 25mm. Sealed bearings do need to be re-greased at times as hydro turbines run 24/7 and see very high cycle rates. The PowerSpout is provided with a re-greasing nipple so this can be easily done with the turbine in operation. Refer to manual for re-greasing schedule. Lower quality and cost bearings like these can be can be used where the turbine is operating at power below 500W and 1000 rpm.