I haven't stress tested it but I have a Spotfinder in my small wallet.

Atuvos one at 1.6mm and UGreen one at 1.7mm are great, though one time battery is annoying. There are some that have wireless charging, though thicker.

	▲	ghaff 8 hours ago \| parent [-]
		SpotMinder is supposedly wireless charging though haven't tried. Have one in my wallet. Will probably get some more AirTags.