Have a total of 5 pieces in February 2014 purchased and initially not rated. Now they are about 11 months in use. The Assembly worked relatively well and quickly. However, now the 1. battery seems already give up the ghost. The smoke detector indicates that in any case already for the 2nd time with a beep and the Batterrie must be replaced. Were included 9 volt lithium batteries block (Made in China). This is of course annoying, especially since the place was mounted on the smoke detector that is not easy to achieve. Let's see when the next battery change is due times.
