When returning from Austria there are still problems to because a battery is installed, and products with batteries and / or acids can not be returned without further ado. Interestingly, when ordering it does not matter whether a battery is installed, but not the back end ??? So an e-mail to the seller (electronics Star) sent to obtain information about the further procedure. Now I'm waiting for instructions from Hifi-Tower (Chal-Tec GmbH.)