Bests & Worsts Reviews from Amazon

It's simple, it's effective, but proper functioning depends on your floor surface. For those who don't want to read thru the end....Conclusion: This is a great and simple solution to keep people from entering your home, while you are at home. But you have to buy additionally a 9V block battery, need a micro screw driver to place the battery and you have to buy a simple fastener solution (see below) for slippery floor surfaces (e.g. wooden floors, stone or tiles) Delivery: I bought it on Amazon. Delivery was this time one day late. Opening: The packaging of the Alarm is tricky to open. Its completely blistered. This is not very Eco-friendly and you need strong household scissors to open it. Content: Just the Alarm, A short 1/4 page instruction. NO battery included. you need to buy a 9V block battery separately. Installation / Functioning: First you need to buy extra a 9V battery... if you realize this only after the packaging arrived, this might be quite bothersome as many households will have AAA or AA batteries always at home but not 9V block batteries. The installation of the battery requires a micro screw drive. A normal screw driver will not get you far as you wil just damage the screw head. Battery once installed you should be good to go. The alarm is loud and it works very effective. But I have a wooden floor and the device always slid away when opening the door. The rubbers on the bottom would hold strong enough to the ground. So I bought this Scotch Reclosable Fasteners, Clear, 1 x 3-Inches, 2 Sets (RF9730) to hold it strong to the ground and the door cannot slide it away. ==> this works perfectly. 1) The door is completely and very tight blocked! This keeps intruders from entering your home AND 2) you can remove the alarm easily while this scotch fastener consist of two parts. One sticks to the floor and the other to the alarm and you can peel the device off any time easily from the floor. 2) The alarm goes safely off if the door opens and cannot be switch off by the intruder - given you have placed the alarm fixed to the ground with the fastener close enough to the door. Final rating: As the obligatory 9V block battery is missing and additional investment into a fastener solution for slippery surface is needed (depending on your home) i can unfortunately only give 4 stars. Once installed properly it works perfect. Open question remaining: How long will the battery last?