Worse than I thought ...

I did alot of things in electricity at home, and I still do.
Until then, I pulled with pliers Stripping beast that was part of a fairly low-end tools suitcase
(That is, the quality of the clip in question !!!!).
To make me happy and make life easier I offered this clip, on which I based full of hopes :-)
Short. Certainly, it is better than my whole rotten clip, but not that much.
It's OK for rigid cables of 1.5 and 2.5 mm2, but as one commentator said "It tears more than cut."
So for 4 mm2 cables I find it quite limited or no practice.
And we must also be careful that the cut sheaths come hinder the mechanism.
In the end, more convenient than my old clip PourRite all, but I really expected more.