A big speaker that delivers big sound, yet vanishes into your room's decor. The 90-RT is perfect for use as stealth mains, rears and side surrounds in a high-performance home theater, or for bringing dynamic sound to alternate zones from your main stereo listening room. Vanishing Series built-in speakers feature our exclusive wafer-thin Sheer-Grille, a magnetically-secured grille that protrudes only 7mm from its surroundings. Sheer-Grilles have nearly transparent, ultra-small perfs, and are acoustically inert, for dynamic, unimpeded sound and more uniform coverage, even in larger rooms. These speakers are timbre-matched to Polk RTi speakers to insure utterly seamless blending from speaker to speaker in systems that combine traditional and built-in speakers.