Abstract: An adjustable bracket and housing assembly mountable to any horizontal or verticle surface designed primarily for passive infrared detective for security systems. The bracket has a mounting member (30), a cylindrical member (20) allowing horizontal adjustability of the housing assembly and a bracket arm (15) having teeth (21) for vertical adjustability of the housing assembly. The housing assembly has a base (10) and removable cover (12). The base is attachable to the bracket arm (15) by a screw (29). The housing assembly cannot be adjusted directionally, unless the cover (12) is removed, thereby providing access to the screw (29). This latter feature makes the unit of the present invention tamper proof as an alarm will be triggered if the cover (12) is removed from the housing assembly.