This is a large gear motor housing.� It is sized to go with our large gearmotors.� This is a high quality sturdy housing.� It is made of laser cut aluminum keyed and welded together.� The structure has mounting screws that match up with the rectangular base.� The housing also has a precut hole for supporting the outer-race of the bearing that comes with our omni-wheel assemblies and large ATR and small ATR wheel assemblies.�� This assembly combined with the above mentioned wheels give an extra bearing support for the shaft and wheel so the motor bearing is not doing all the work giving better performance, longer life, and increased weight handling capacity.