STV have produced a wide range of pest control systems & weatherproof baits for a wide range of unwanted guests in & around your home or work place. This simple plug & go pest repeller is ideal all around the home & will give years of protection & peace of mind from rodent activity in your home. The STV789 Combines swept ultrasound & electromagnetic action this travels through the wiring system of your home & will target nest areas within wall & ceiling cavities & drive out rodent pests & at the same time the unit is inaudible to humans household pets & safe to use around children. This unit works on EMC pulses through wiring to reach nest sites within walls ceilings & floor cavities & the unit has a test button & halo-red LED indicator to show unit is in good working order. PLEASE NOTE: Harmful to domestic pets such as Hamsters & Gerbils.