Wireless Flash Trigger Yongnuo RF-603 Transmitter can be used as receiver, and receiver also can be used as transmitter.
RF-603 is equipped with the Auto-Sensing Transceiver Technology that enables it to change automatically between Transmitter and Receiver modes. When a hot-shoe or other trigger is detected, it automatically switches to Transmitter mode. With Auto Relay Mode you can trigger a remote camera in sync with remote flash. Remote trigger the camera shutter and flash at the same time by one RF-603 kit.
Features and specifications:
Flash synchronizing speed: up to 1/320s (depends on camera / flash model 2.4GHz band/16 selectable operating frequencies for eliminating interference Shutter Release: half-way Focus and full-way press Shutter Shutter Interface: 2.5mm socket Studio light interface: standard PC socket Battery: 2X AAA batteries (Not included in the package) Stand-by time: up to 45 hours (AAA battery) Size: 37mmx30mmx81.5mm