Description
A GPS tracker is cheap, small, and held on by a magnet. It does not need to be clever, because most of the time it is not transmitting at all. It wakes, reports a position, and goes quiet again, which is exactly the behaviour that a signal-only detector walks straight past.
The VIM-BUGDETECT15 works two ways for that reason. An RF sweep from 50MHz to 12GHz catches trackers, tags and wireless bugs while they are talking, and a flexible magnetic probe finds the magnet holding a tracker on whether it is transmitting or not. A 17 level LED meter does the guiding, there is no app and no phone pairing, and the 2000mAh cell runs about 20 hours.

