excellent product comes with a 9V battery is German, France parcequ'en we no longer make anything :( quick installation barely 2 minutes, commissioning and simple, I opened the gas and 1mn30 after the siren sounded to the postman rang at home and exploded, no I joke:>), I highly recommend the purchase of this product, shipment by DHL of Germany, and the mail, beginning one week, so I can sleep on my two ears in peace, I'll buy one for my trailer