The Model 339 On/Off Delay Relay is an electronic time delay relay which provides two functions: on delay, and true off delay. The true off delay, (relay remains energized for a delay period when power is removed) is provided by means of an internal latching relay. Each time delay, on and off, is separately adjustable to a maximum of five minutes on or off. The Model 339 uses the same pin-out configuration as standard time delay and general purpose relays. It can be used in new or replacement applications for thermal, pneumatic, or spring-wound timers, or in place of general purpose relays or other electronic timers.