I installed Smanos K2 the other day and it was relatively easy although the instructions were a little light on. I got through it unscathed and it all works as described so we have peace of mind knowing our house will be very noisy and that I will receive push notifications should someone break in. The individual pieces look great once set up which is why I guess I went with the design in the first place. Just looks smart! Just some points worth noting from my experience with the installation: 1. I hope the self adhesive tape holds the DS20 as there were no tiny screws for these. I screwed all the other units onto the wall rather than use the double sided tape. The tape is good if you’re renting. 2. I’d like to have seen more installation options in the literature for the DS20. I figured it out different configurations using the test mode as not all doors and windows have flat surfaces making it a straight forward installation as shown in the pictures. 3. The siren I found out can be installed on a wall or the ceiling. I was a little confused as the back plate “up arrow” makes you think it can only go on the wall. 4. Would be good if you could buy individual DS20’s instead of having to purchase a pair. 5. Didn’t know before purchasing but the motion sensor is best placed at 90deg instead of directly in front of someone’s walking direction. It cannot be placed above 2.2m on the wall either making it relatively easy for an intruder to pull/smash it off.