The Tannoy CMS 803 PI 16 OHM BACKCAN is an acoustically enhanced, zinc-plated steel back can designed for the pre-installation of CMS 803 PI series ceiling loudspeakers. This accessory allows installers to fit the back can into newly constructed, non-suspended ceilings during the initial construction phase, while the loudspeaker itself can be installed later. This back can is designed to offer enhanced audio performance, particularly in the low-frequency range, and has a low-profile design that makes it suitable for shallow ceiling spaces. It is also fitted with a low insertion loss 60W line transformer, which improves power handling and sound quality when used in constant voltage systems.