The D2 Alternating flasher is an adjustable speed, 2 channel flasher designed for the widest possible range of uses. The outputs are entirely solid state so there are no sound when it operates and no relays to wear out. There are two outputs channels that alternate with each being ON for 50% of the cycle. Two speed ranges can be selected so the cycle speed adjustment can be smoothly changed from 4 times per sec to over 1 minute.