More reliability for less cost. Available in Ionization, Photoelectric and combined Photoelectric/Thermal models; for spot and duct installations. Each features in-place sensitivity measurement in %/FT. obscuration to satisfy NFPA 72, Chap. 5. UL Listed, in rugged, low profile design for every aesthetic environment. Two and four-wire base options. ULI compatible with a broad range of alarm and suppression controls.