The Ultimate Alerta Bite Alarm Set 4+1 offers reliable bite indication with a range of up to 400 meters and a frequency of 433.92MHz. The set is weatherproof and equipped with convenient features such as a dropback function, night light and memory function. The receiver features a vibration function and silent mode. In addition, the set has detachable snag-ears, a 20-second locking LED and a rolling code system for added security. Tone, volume and sensitivity are adjustable, and there is an expansion box for additional functionality.