So returning to Amazon and ordered now XXL.
The part itself should its purpose to cool and cold days perform well, especially when I get delivered the right size.
Because of returning my time was wasted and deducted 2 points, because it's not an isolated case.
Addendum:
Reimbursement by Amazon was very quick.
The super-sized version fits very well. I can now use the velcro strap as opposed XL version to the narrowest point, without having to move the belly or apply pulling briskly.