Water Bottle Opener NBF

I designed this simple "water bottle opener" for my 91 year old grandmother. It fits on the german bottle type "Normbrunnenflasche (NBF)" which is made of glas and has an aluminium cap with 45 notches. We had a lot of different bottle openers but they didn't work well for this kind of bottle because they don't have 45 notches. So here it is, a very simple bottle opener for the 0.7l "Normbrunnenflasche" with exact 45 notches.

Update: I made another version for the cap with 38 notches. It can b