No nicks in the wire, no small strands damaged. Just bare wire. There is another guide that lets you control how much insulation the tool removes along the length of the wire. The idea is you ...

Leave the ring of insulation attached to help. (Trim if desired.) Tighten with a screwdriver. For clamp-style terminals: No hooks or twisting are needed. Trim solid or stranded wire to length and ...

When an insulated wire is placed in the slot and the appropriate amount of downward pressure is applied, the slot cuts into and moves aside the plastic insulation, exposing the conductor within.