I wonder if the 23mm is a typo. Maybe it will turn out that they do not make a 23mm after all?
I was wondering exactly the same because the information so far is mix and very confusing, for example checking one review at youtube it shows the back of the box where the mod comes in and it shows the sandstorm on 25mm AND 22mm (yes 22mm not 23mm) then you go to JV website and shows the sandstorm size more like the mod can acommodate tanks FROM 23mm TO 25mm not like is two different options. Pictures of the 2 examples below;