Detailed Product DescriptionLocal Taqween University Of Islamic Sciences, Karachi ISNA (Islamic Society Of North America) Fajr TimeMuslim Doorbell HA-1013Put the machine on the door inside.Put the small magnet on the door case.Put the arrow of magnet in the front of red arrow in the machine.Remain space between the magnet and machine about 1.5mm.After you testing the machine teak sticker out then stick the machine.For more steady using the nail where batteries emplace.