length and opposite the aperture 33 adapted to slidably fit within mounting slot 40 is permanent mounting bracket 41 mounting bracket 41 may be constructed like housing 12 of practically any strong rigid material and in the preferred embodiment is constructed of aluminum mounting bracket 41 has a raised t portion which slidably engages mounting slot 40 of housing 12 bracket 41 is permanently mounted on a rigid surface e g a wall by means of screws 42 located on its face also provided for mounting the housing 12 is temporary mounting bracket 43 temporary bracket 43 is constructed of a high impact plastic as it requires a slight degree of flexibility for mounting about a door frame like permanent bracket 41 temporary bracket 43 contains at one end a t for engaging mounting slot 40 of the housing 12 at the other end of bracket 43 is a flange 44 for engaging a door temporary bracket 43 is of a width slightly greater than the width of a door such that the flange 44 may be hooked about the inner or outer face of a door and the door then shut about the bracket 43 this secures the bracket 43 to the door frame and the housing 12 may then be inserted thereon providing a temporary yet secure attachment for the housing 12 to lock the housing 12 onto the bracket 41 or 43 a cylindrical locking pin 45 is provided as illustrated in fig5 pin 45 slidably fits into an aperture 47 which is perpendicular to the slot 40 and near the lower corner of the housing 12 and slot 40 pin 45 is of a large enough diameter to block the slot 40 and thus to prevent the housing 12 from sliding off of bracket.