Abstract: An indicating assembly designed to be used primarily with container assemblies of the type used for mail depositories installed in multi unit apartment houses, condominiums, or like multi unit dwellings. A switch installed in direct association with the opening of the main unit of the apartment complex, wherein the switch is interconnected in circuit between a power source and an electromagnetic indication device. Opening of the switch and thereby breaking of the circuit is caused by the post office delivery opening the main assembly normally required for the disposition of mail in the individual mail boxes or compartments. Breaking of the circuit causes disengagement of the electromagnetic device with a base element formed from magnetically attracted material such as metal.