The MTC-14WG and MTC-16WG high humidity optional grilles address the weakest link when using ceiling speakers in high humidity applications, a steel grille that can rust. High humidity grilles extend the longevity of JBL's Control 10 Series model ceiling speakers - Control 12C/T, 12C/T-BK, 14C/T, 14C/T-BK, 16C/T and 16C/T-BK - (plus Control 26C and 26CT) when used in such applications. The aluminum alloy material does not rust and the durable powder-coated finish prevents pitting that could otherwise occur with raw unfinished aluminum. The finish provides a nice look that matches with the speaker. The speaker upon which the grille is utilized is intended to be installed in normal ceiling speaker orientation, with the speaker mounted into a horizontal surface (and protected from the bulk of direct weather/water exposure by the overhang of the surface), with the sound projecting downward. To use the grille, simply install onto the speaker instead of the grille that comes with the speaker. Note that care should be taken to press evenly when press-fitting into the speaker so as not to dent the grille via too much pressure concentrated into one location. Pressing closer to the edges is recommended. A scrim is glued to the back of the grille to help break up driving precipitation that might reach the speakers. For painting, do not remove the backing. Paint grille lightly enough to color the grille without clogging the grille backing. For additional rust resistance of the speaker in particularly tough environments, the installer may optionally choose to replace the dog-ear screws with stainless steel or other highly weather-protected screws of the same size and length (the installer should run the dog-ears fully down and back out again prior to speaker installation to avoid the possibility of dogear channel damage).