JBL-LCT 81C/TM is a full-range ceiling speaker designed to lay into a 600 mm x 600 mm metric suspended grid ceiling, with no cutting of ceiling tiles required, making for an easy and cost-effective installation with a minimum of mess. The low profile depth of only 103 mm (4.1 in) allows the speaker to fit in locations where deeper loudspeakers do not. This loudspeaker is designed to provide excellent performance for voice reinforcement and light-to-medium music in a wide variety of applications, including education classrooms, business music systems, retail stores, music/paging systems, airports, reception/waiting rooms, lounges, courtrooms, meeting rooms, and more. The very high sensitivity of 96 dB provides maximum sound level, even at low tap settings. JBL-LCT 81C/TM includes a 200 mm (8 in) dual-cone driver with a very high 96 dB sensitivity. The driver features a 25 mm (1 in) diameter voice coil with a Kapton coil-former and high-temperature wire for better power dissipation and long-term reliability. The speaker's built-in 10 Watt transformer provides versatility by allowing use on 100V or 70V distributed loudspeaker lines, as well as at 8 ohms (low impedance) for driving directly from a low impedance power amplifier. Adjusting is convenient via a rotary switch on the side of the rear enclosure. Two safety seismic attachment tabs are provided for securing to ceiling deck, plus 4 holes are provided -- one in each corner. The color of the perforated grille is white.