[Jeff Chandler]

Probably worm drive.

[fireman15]

I have one of these. Mine is older so only one screw holds all the guards on. I use it without the guards about half the time. You can operate the switch with one hand while holding onto a ladder with the other. Even though it has only two 5" counter rotating blades... it has a lot of torque. I think that with its light weight and maneuverability, with its guards off and extended out in front of you it would be a superior to a full size tool in a circular saw fight.

[fireman15]

But this is why you should always carry an easy to start dependable chainsaw with a long bar for self defense. Sometimes there isn’t an extension cord handy.

[Freestate316]

Thirty years ago, I was working for my brother, a Philadelphia area contractor. We had a guy working for us who used to wedge the guard open on the worm-drive saw. He was cutting through a board when the saw bound and kicked back. The blade, at full depth, went across his left thigh. We saw it happen, and it was gruesome. He made a full recovery.