The CDT countdown timer, is a timer control for use with signaling devices. The CDT allows the time period to be adjusted on its faceplate (protective cover). The unit is supplied with an On/off switch that holds the current time position when turned to "off"(used for breaks, pauses in production, etc.)and a Reset push button to restart the time cycle from the beginning. Standard programming is as a countdown timer, that reaches its predetermined time "zero" and begins to accumulate time as a negative, and also closes a contact that can be used to switch a signaling device (choose from our various signaling options from our site). Once the Reset push button is pressed, the cycle starts over. 120 Volt AC power cord of 6 foot length is included, wiring to the particular signaling device is simple by running interconnect power wiring (customer supplied) to that device. DC Voltage unit available (select when ordering). Custom versions are available, and may be added to signaling assemblies on our site--please inquire.Four Digit Display, characters are 3/8" tall--viewable from 20 feet. Contact (either N.C. or N.O.) is rated for 3 Amps at 250V.