Each of the first and second open slots 802 and 804 is configured to receive a body of a fastener e. g. , a screw and block an enlarged head of the fastener. Each of the first and second open slots has a respective width that is larger than a first width of the body of the fastener and smaller than a second width of the enlarged head of the fastener. When the mounting plate 800 is being mounted to a surface, the respective fasteners are fastened onto the surface via the first and second open slots, thereby holding the mounting plate 800 between the enlarged heads of the fasteners and the surface. Before the respective fasteners are tightened onto the surface, a position of the mounting plate 800 is adjusted by moving the mounting plate 800, including the first and second open slots, with respect to the respective fasteners. The first and second open slots 802 and 804 can therefore define two perpendicular directions of adjustment for the position of the mounting plate 800, and each of these two perpendicular directions of adjustment is associated with a respective range of adjustment defined according to a longitudinal size of the respective open slot. Further, in some implementations, the heads of the fasteners fastened into the first and second open slots 802 and 804 rises beyond the front surface of the mounting plate 800 by a head height. Referring to FIG. 7B, the rear exterior surface of the device housing 702 may include a second recess 724B and a third recess 724C configured to cover the heads of the fasteners fastened into the first and second open slots 802 and 804, when the device housing 702 is mounted onto the mounting plate 800. Each of the second and third recess 724B and 724C may have a respective depth substantially greater than the respective head height of the fasteners fastened into the first and second open slots 802 and 804.