Electronic Bird Repeller The Bird Gard Super Pro PA4 is specially designed to broadcast unique low frequency sounds. Certain bird and animal sounds are of lower frequencies that require a special PA speaker. The PA4 is available with one, two, or four PA speakers depending on the size of the area needing protection. Each speaker covers up to 1.5 acres (0.6 hectares). The PA4 incorporates multiple random features designed to prevent habituation. With all four speakers connected, every six seconds a randomly selected sound is broadcast at a randomly selected frequency out of a randomly selected speaker. With two speakers connected the sounds will alternate between the two speakers. A user-replaceable EPROM recording chip can now be easily changed in the field in order to use different recorded sounds. Available sounds for the Bird Gard Pro PA include Great Blue Heron, Wild Turkey, Snowy Egret, Great Horned Owl, Black Crowned Night Heron, Jackdaw, Carrion Crow, Coyote, Dog Pack, Canada Goose, Wolf, wild cat, motorcycle, shotgun and others. Many different pre-recorded configurations are available. The electronics of the Bird Gard Super Pro PA4 are designed to handle the PA speakers (these speakers cannot be plugged into any of our other units). The generating unit features solid-state electronics mounted inside a NEMA-type control box for weather protection. It mounts easily to a post or pole using the included mounting hardware and brackets. System includes the generating unit with one built-in amplifier, one PA speaker with 100 feet (30 meters) of cable, power adapter with 50 feet (15 meters) of cable and a 10 foot (3 meter) battery cable with clips.