simply push into the ground in the middle of mole activity. completely harmless to the moles our sonic repellers discharge a sonic pulse into the surrounding earth every 30 to 40 seconds. available in two models battery powered (each unit requires 4x d batteries not supplied which should last 4 to 6 months). one unit covers an area of up to a maximum radius of 15m (16.4yds). simple & quick home assembly (no tools required).