The Bird Barrier Bird Gard 110v Pro 1 (sw–bg40) is an electronic bird repeller. It is programmed to send a specific distress signal and predator calls to alert other birds in the area. This type of product effectively repels birds such as pigeons, starlings, seagulls, sparrows and others. Units are programmable and have on-off and a volume control feature for your convenience. It also has a time-off sound and a 24 hour day and night switch. This is ideal to put in small areas to effectively block flocking birds away from your house or building. It's available in two models and plugs into 110 volt power outlet.  The Bird Barrier Bird Gard 110v Pro 1 (sd-bg40) emits sound in a cone-type pattern that can work effectively to deter birds from roughly 100 feet away from the unit.