Features 2 buttons for alarm system to turn on and off and 2 programmable buttons with part/alternative activation functions (also programmable for direct commands of the HBT receiver), emergency call or panic (direct siren activation).Supports bi-directional communication: confirmation of operations through optical feedback. After you send the commands "ON", "OFF" and "ON", the LED will display the result (green = OFF; red = ON or partial). Small and ergonomic, ready to attach to key chain.