Easy to install, a small screwdriver size 0 Philips or Pozi is all you need.
Select the frequency using the DIP switches (very small switches in a small plastic block) e.g. 2,5,6 ON and then set that on all the receivers.
On each receiver you can select one of four channels. As I am using the system to switch off everything non-essential when I go to bed or leave the house, I set all the receivers to A.
Unlike many other systems there is a separate on and off, I know other systems just toggle so you don't know whether the devices are on or off!
Another reviewer mentioned that they had trouble inserting plugs into the unit, I have not had that problem.
I bought nine of these, three are dead, the remaining six continue to work without incident. These are made in China, no doubt, although Brennenstuhl name sounds German and you hope for a made in Germany product.... no. I found the representative on enquiring Chinese contacts;
Mr. Wilson Wu, Hugo Brennenstuhl GmbH & Co., Kg, Room 2306B, No. 132, Renmin Road, Ningbo, Zhejiang, China, 315300
Disassembling the device is tough, but possible, the fault lay in the relay used to switch the current, it has fused shut and therefore couldn't be switched off. The relay is rated for a maximum of 2A at 250V, so switching something with a heavy, inductive load is going to kill this (be careful when connecting to motors, lights and heaters).
Due to the 33% attrition rate, I'll dock two stars off my five star review.