Most court ordered GPS monitors clip on the ankle and may be worn invisibly on the calf.
Never heard of a GPS monitor with the form factor of a boot or cast, but the GPS can be integrated into anything that the perp can't easily remove without activating alarm -
maybe Mike Pompeo has a custom GPS boot monitor rig , but wouldn't we have read all about that in RR news?
/s
https://www.gabriellawteam.com/when-will-the-court-order-a-gps-monitoring-device/