Hi, I want to get one of those razors which have a blade covered with a surrated edge - I THINK they're for thinning hair.

Name: $_5777.jpg Views: 696 Size: 49.9 KB

My questions are:

1) Any one used them to confirm they're for thinning?
2) I want to use it to keep the back and sides of my head shaved a mm (not shaved clean or I'd use a straight razor) is this possible?

Any help would be great! Thanks!!