2.4GHz band-16 selectable operating frequencies to eliminate chance of interference * The RF-603 transceiver system can be used to trigger all studio flash units thro standard PC socket * Flash sync speed: 1/320s; Operating distance: 100m * Shutter interface: 2.5mm socket; Release: half-way press, full-way press * Battery: AAA x 2 ( NOT include ); Receiver stand-by time: up to 45 hours