GPS device? just lock the tool box down where ever it is being stored. The harder and more complicated you make it for someone to get the tool box or the more you slow them down the less likely they are to even try. **** used to get stolen out of our garage a lot until we wised up and just locked everything down with large cables and heavy duty locks. There's no need for a GPS device.

 

FWIW, most of my tools are Craftsman (lifetime guaranty) and I've owned many of them for over 50 years. Only had a couple break (and it was really my fault but they replaced them anyway). It may not prevent them from being stolen but I use an electric engraving tool and put my last name on every piece. Especially helpful when helping someone else with a project and other folks' tools are involved.