Bottle Cage AirTag Bracket.

Put an Apple AirTag below your bottle cage. If your bike is pricy we recommend placing two iTags on it as thieves these days are most likely to check under the seat and iTags secured there are usually relatively easy to remove. But if they find one there is a good chance they won’t look elsewhere also an iTag under the bottle cage can be fitted using non standard bolts. A small thing but effective for ensuring thieves who have a hex key on their person won’t be able to remove the iTag on the spot is to use security screws, such these:

https://www.accu.co.uk/en/67-security-torx-button-head-screws

These parts are designed to be easily printed by FDM machines with minimum support (custom support is built into the .stl file).