My dog is a Newfoundland, included the necklace was obviously too small (but usually this does not surprise us!), So I bought a child's belt, simple, the same width, and c is impeccable!
After a few adjustments of the collar (mainly investment and tightening the housing to be located at the dorsal neck, too much hair below!) And implementation of long electrodes, the collar works fine. I have taken time to use it after receiving the fact that there is a behavior change, the "jump" to the visitors (with us, no worries) ... which forced us to 'lock up garage during visits (+ barking, seemed very domineering with others etc ...) ... just a small discharge (level 2 or 3, it is insensitive to 1 -pourtant, tested by me, it is not a caress !! -) during the order given at the same time when he jumps (80 kilos that jumps at you, even if for playing, it remains fairly pleasant, and this can be dangerous if the person is fragile!)
In short, it rolls, it understands and calmed down immediately!
Happy with my purchase!