The Molechaser- Weatherproof and proven effective at getting rid of moles, voles, gophers, shrews, and other burrowing rodents- Sends 300Hz sonic pulses at 15 second intervals- Can be buried flush to your lawn, keeping it from obstructing your landscaping activities- Change batteries with convenient cylinder while the unit remains in the ground- Batteries: 4 D alkaline- Battery Life: 4-6 months- Coverage: 9,000 square feet 1/5 of an acre- US Patent Number: 6157594