Key Features: Ultrasonic noise/sound generator Connect to a loudspeaker or mount to a vehicle Works on a variety of small animals and insects Can connect up to 5 piezo loudspeakers May or may not have a frequency adjustment knob. Some units will have a flat adjustment with a slot to insert a screwdriver to adjust the frequency. Through ultrasonic sounds it is possible to scare away animals and insects like rats, mice, martens, wild rabbits, mosquitoes. If mounted on the car, roe will be put to rout (decreased danger of accidents). Connection of a piezo-treble loudspeaker to the module is an ideal way to scare away destructive animals out of your pantry, kitchen, storehouses, garden, etc. Also can be used as dog whistle. Even some birds species will be scared out of your fruit trees.Item SpecificsOperating voltage: 12 - 15 V/DCCurrent consumption: < 50 mALoudspeaker output: up to 5 piezo loudspeakersAudio frequency: adjustable ~8 - 40 kHz (± 20%)Size: 60 x 45 x 29 mm (without fastening straps)A speaker and power supply are required for unit to function properly. Indicator light will not turn on without a speaker and power supply wired to the unit.NOTE: May or may not have a frequency adjustment knob. Some units will have a flat adjustment selector with a slot to insert a screwdriver to adjust the frequency. See photos for unit variations. We do not accept requests for specific configurations. Recommended Speakers (required, not included):L001 - Piezo spherical dome tweeter with flareL002 - Ultrasonic wall loudspeakerL003 - Piezo-tweeterP5123 - Mini piezoelectric tweeter for M094N