This device is used to check the functionality of the proximity sensors in KPNP's electronic socks (e-socks) for Taekwondo. 

The tester is an auxiliary system that ensures the electronic gear is working correctly and is ready for competition. It can be used to verify accurate sensor response and perform a real-time system check before a match. Some models, like the K2 E-Socks Tester, show the exact position of each working sensor, providing a clear and precise check.