Wall-mount speaker-strobe models with field-selectable Candela settings of: 15/30/75/110cd, or with field-selectable High Candela settings: 135/185cd – Mounts to 4” (10.2 cm.) square –x– 2-1/8” (5.4 cm.) deep back box. An Optional Extender (SPEXT) can be used for mounting ceiling-only appliances to 4” (10.2 cm.) backboxes. No extension ring is required for Siemens Series ‘SE’ appliances used in wall-mount applications. High-efficiency design for maximum output at minimum wattage across a frequency range of 400 to 4,000 Hz – Field-selectable taps for 25 or 70 VRMS operation from 1/8 Watt up.