CB - the back plate is a piece of aluminium coloured to match the stat ( of which there are multiple ccoulours including pink !!!) the plate is larger than the width of the stat with with holes in each corner so when the stat is stuck to the back plate you can the screw the unit into the wall or frame etc. Simple but works fab
The probes also read humidity and air pressure
With regards to having the minimum temp range lowered to 4' - Im sure the temperature gives the game away there
Mark