... 4-way type of power control system, large-span torque.9. 7-vane type high performance air motor,high efficiency, no impact ... ± .6. Shift high/low speed mechanically , greatly promote working efficiency.7. Reaction arm of high strength ,anti-easily-broken, adjustable by ... 8. Equipped with brake & cutoff system to protect the operator.9. New ergonomics-design handle, which is freely connected with drive ...