The QK79B is one of three Light Dark Switch kits in the QK79 series. If you would like all three LDR kits, you are looking for QK79
12V relay rated to switch 240VAC/5A mounted on-board. Using a relay allows the light/dark switch to form a module separate from the circuit which is to be switched. The Common, Normally Open, and Normally Closed contacts are brought out to terminal blocks. Power is also brought to the kit through terminal blocks.