The Yarden 8-T High-Performance Ceiling Tile Stereo Speaker features a Kevlar(R) woofer, four pivoting titanium tweeters, complete K-overage ESD (Equal Sound Dispersion) design for almost 180 degrees of sound dispersion. It features speech mode to improve intelligibility, music mode for an extra wide frequency response and stereo and mono modes to fit any kind of installation. It also features a magnetically held grill (with two security screws) for time saving installation, 2nd level cross-over design and multi-tap power transformer for selecting 8? (bypassing the transformer) or 70V/100V power settings that are suitable for an array installation.