24 Hr Countdown Timer 24VDC – Similar functions to the ISG12 & ISG24 above but all carried out electronically. Use the up/down buttons to preset the desired number of hours. Press Start, the internal contacts are switched, and the digital display shows the time to be counted down. The display changes every minute to indicate remaining time. At the end of preset time the display shows zero and the internal contacts switched back. 1 x set C/O contacts rated 24VDC 1Amp.