So, do you know what this key was for? I know it looks like a key to wind a clock, but nope, it is a radiator key. We used to have that key at our house for our heater when the heating was on the floor to turn the heater on and off. It bring so many memories of Winter and also Christmas.....Now we moved to an electric heating system, so everything is easier, but not as magical as in the past. So did you know what it was. Please SHARE if you remember these kind of keys :)