National Time is pleased to reintroduce the impulse time system with today's high tech performance! Microprocessor technology has replaced the slow, troublesome spring/ratchet/solenoid engagement designs currently offered by other manufacturers. National Time's revolutionary Rotary Drive time system can instantly correct all of the building clocks to the exact hour and minute at any time of the day! With our on demand instant time correction, you no longer have to wait up to twelve hours or perform confusing, tedious sequences of manual stops, starts and resets. We give you the correct time when you need it --- NOW! Rotary Drive guarantees to outperform all existing clock technology without sacrificing the unsurpassed durability you have come to expect from National Time's synchronous motor drive systems. Each clock is equipped with an all metal case, convex glass crystal, and white polystyrene dial having black markings and hands. A sway-proof hanger plate is furnished that securely holds clock to wall. Cases are attractively finished in powder gray enamel. Other finishes and shatterproof lens are available upon request. Shatterproof lens now standard on 12" round.