The Sunpak DSU-01 Digital Slave Unit is a wireless digital slave that mounts on the bottom of almost any shoe-mount flash for remote firing. It can be used with flashes equipped with a hot shoe or sync cord. The DSU-01 provides a white light slave trigger that is adjustable so the flash fires after detecting up to 4 pre-flashes from cameras using pre-flash bursts to determine autofocus and exposure. The DSU-01 is equipped with both multi-flash and synch terminals, a pre-flash cancellation mode and a manual setting. It accepts standard or mini-jack PC cords and standard flash units with a central contact and is powered by 2 coin type CR-1220 Lithium-ion batteries (included).