STV649 is a product which can be used to deter dogs from persistent barking. To use this product: Remove all packaging and carefully read the instructions. Separate the Main Module from the Mounting Bracket to the rear by sliding it up and out of the retaining slots. Remove the cover of the battery compartment at the rear of the main module by unscrewing the retaining screw and sliding off cover. Insert 4 x Alkaline LR20 D 1.5v batteries (not included) and replace cover. Locate the Mounting Bracket securely onto any outdoor vertical surface using the fixing screws provided. For further information on assembly and mounting an Instruction Leaflet is provided in-pack. Slide the of the main module downwards into the retaining slots of the Mounting Bracket until it clicks postively into place. Adjust the rear mount so that the speaker of the main module is aimed into the territory where the dog is barking. Select the sensitivity setting required. Turn the unit on using the ON/OFF switch within the control panel at the front of the main module and then replace the Control Panel cover. The unit will activate after a few seconds delay. Check the sonic output by pushing the red Test Button within the main module. Once it is set up and in position leave the unit operating constantly.