Ankle monitor 电子脚镣
An ankle monitor (also known as a tether, or ankle bracelet) is a homing device that individuals under house arrest or parole are often required to wear. At timed intervals, the ankle monitor sends a radio frequency signal containing location and other information to a receiver. If an offender moves outside of an allowed range, the police will be notified. Ankle monitors are designed to be tamper-resistant and can alert authorities to removal attempts, such as cutting the conductive band causing a circuit break.