Conclusion: Stay away!

I had ordered this device for securing a door in an apartment building. The idea that you (have been delivered two) by means of a mechanical key could switch the device sharply, I liked right away. But then the device is recognized and the initial euphoria quickly gave way to great disappointment.

For operation of the instrument I can not say much more, because I have not even taken the instrument, since it had a serious drawback: The battery compartment of the device is clearly attached to the front and contrary to other reviews, had not my device security against unauthorized opening of the battery compartment. No Schaube, no lock, no!

So could any burglar, within 2-5 seconds, locate the battery compartment, slide open and remove one of three batteries, turn off the unit. This is simply unacceptable for me! If a burglar wants to turn off an alarm, then he should have no need at least minutes and few seconds for it ...

Although I expected at the low price is not much of this product, I have decided because of the many good reviews for the purchase. This was a mistake. The unit I have sent back, but had to bear the return postage yourself (Amazon.com Marketplace).

Conclusion: Stay away!

UPDATE:
I read more and more in the new reviews that the battery compartment of the new devices is secured with a screw. I suppose, therefore, that the manufacturer has developed its product. If this is factually correct, then my review would be invalid.