The Carlo Gavazzi DBB51 timer is a true delay on release timer with a knob adjustable time range from 1 to 10s. It has a combined AC and DC power supply, providing flexibility in installation and application. The DBB51 operates when the connected power supply is interrupted the set time period starts. At the end of the set time period, the relay will release. If power supply is reapplied before the relay releases the time is reset and the relay will remain on.