[How to use]: Put the bit over the screws/bolts first, Start with the lowest speed, slightly Apply pressure to remove the burr and Increase the speed as needed. Do not turn on the driver until the bit fully covers the screw/bolt. Otherwise, the bit would bump over the screws/bolts and become hard to control.
[Wide Application]: Effective for hardened steel, mild steel, copper, brass, wood, fiberglass and hard plastic. Can be used on some stainless steel scews/bolts but need to be cautious. If there are noises that sounds like too difficult, then quit doing that.