Property me both Optime II and III can send to compare them. As it just so goes, ran me out of the return time and now I have just two. The 2er contained subjectively no worse than the 3, but is laterally narrower lot. Thus, it fits my 10th son without any problems and also to me is simply less "in the way".
Would I choose again, I would therefore buy only the 2er - I am very satisfied, the "insulation performance" is for everyday use with drill, etc. more than adequate.