Features: TRIO 300 offers world’s first integrating three functions of TENS, EMS and Micro-current, plus programming capability in a palm-sized unit. Keyboard Lock function * Five free program memories, 10 steps each. * Previous therapy modes and parameters kept in the memory. * Memory maintains contents even when the power is off. * Different parameter settings possible on each channel * Safety oriented design: - Self-test, constant current output, zero start off output. * Other functions: Digital timer, low battery power warning, automatic power off.