5x11x5 is the size of the one on the sensor board side. The reedy 866 and 877 are bearing killers i guess as i know 4 people plus myself that had the output side seize up. I ordered ceramic bearings from Boca Bearing because reedy and amain are out of stock. It was like 32 bucks with tax for the 2 bearings but they are ceramic so it will help me crash less? Lol