Those seem to be out there, from my Googling last night. Collars with a little pouch built in meant to hold an AirTag (or other similar size tracker). It's closed up, free from any slobber or accidental swallowing, etc. If you're got an adventurous, curious dog who likes to "travel" (escape) and explore, that might be some peace of mind.
If Jasper was still an outdoor kitty, I'd probably already have one. Because getting him to come home/inside at sunset that first year of his life was getting to be a challenge! It's very hard to look for/find a black cat at night, as it turns out.
