The UHT25C-U51-8 are 8" diameter single voice coil loudspeakers equipped with dual (whizzer) cone and 10 oz. ceramic magnet to deliver extended frequency response with high intelligibility and minimal distortion. Cost-effective units are complete with fire-retardant moisture-proof cones, factory-mounted transformer, 6" color-coded leads, and a 51-8 baffle. UHT Series loudspeakers have a 1" dia. voice coil, a 25-volt transformer, and DC blocking capacitor for line supervision applications. To comply with UL requirements, loudspeaker packages must be used with UL-approved enclosures.