Airtag donut for Hydroflask and Thermoflask

This is an odd creation. My daughter lost her ThermoFlask, we walked around her entire school and never found it. I got the bottle as a 2-pack from Costco, I didn't want her to lose the other one and be forced to buy another two. So I made this to seamlessly add an Apple Airtag to the bottle instead of sticking it to the side or dangling it to the cap. I made it like this in order to use the waterproof holders I had.

You'll need to get a waterproof Airtag holder like the ones pictured where you can stick it to the bottom of the bottle and there's a cap that twist on/off for battery change. Be mindful that the cheaper one shown as a 4-pack has a weak adhesive sticker so you might want to use better foam tape. Anyway, you then add the donut by adding good 3M foam tape to the rectangular area and put on the boot that came with the ThermoFlask. The hole in the donut is to help drain/vent water after rinsing off the bottle. 

I have used this for two years now, putting the bottle in the fridge is not a problem either and it's helped finding it a handful of times. I made one that fit the 32oz and 40oz Hydroflasks as well.