Before this I used a Dremel rotary tool to do all my engravings and it was nearly impossible to write on anything to the circular motion of the bit. This bit does not move in a circle, it moves in a back and forth reciprocating motion allowing much better control over the fine tip. The stock bit seems plenty strong for most materials including tools such as a hammer and several pairs of police handcuffs. Nothing I have used it on seems to phase the bit so far. I would recommend this for anyone looking for a simple engraver.