Veckle Clear Fanny Pack Stadium Approved - Fanny Packs for Women Men Water-resistant Waist Bag, Clear Purse Transparent Adjustable Belt Bag for Sports, Travel, Beach, Events, Concerts Bag, Black
www.amazon.com
if not there are a few options on amazon, I'm sure they're all pretty much the same, and quite possibly they may just all resellers selling the exact same item.
One issue with cases that follow the shape of the Airpod Pro case closely is that the lid bit has a tendency to fall off because there's not enough vertical surfaces on the Airpod itself for the case to get a good grip on - and I solve that just by using a small bit of double sided tape to attach the lid part of the case.
The other thing to note about clear cases is that whatever they say about 'anti yellowing' it will happen eventually. It's just the nature of cheaply made clear TPU - but these things are cheap to replace a year or two later if that bothers you anyway.