Bests & Worsts Reviews from Amazon

I have three of these. One is used as an instant on alarm for a door that nobody is supposed to EVER open. The alarm is LOUD AS THE DICKENS !!! I mean LOUD LOUD ear hurting loud. That's a good thing. The other two are used as door chimes for every time a door opens (in our case at our place of business). Th unit comes with both screws and double-sided pressure sensitive tape. Installation is a snap. They will mount on either side of the door, too. Setting your 4 digit code is also a no-brainer: hit the learn button, then enter your 4 numbers on the keypad. See the green light. You're done. If anybody has a problem with this thing, then they are expecting it to be something it is not. Oh, of course it has batteries. And they are not included. So get some and quit whining. For what it does, it does it well... and for a peanuts price, too. HIGHLY RECOMMENDED.