Specification: YN-560 IV Flash Speedlite is a combination of YN-560 III and YN560-TX, Functions: •YN-560 IV can be used as master unit, provides 3 independent groups with controlling abiligy, realizing remote control the flas mode, flash output, and focal length of YN-560 IV and YN-560 III. •One YN-560 IV can receive the wireless signal from YN560 IV, YN560-TX, RF-603 II and RF-602, with optical 16 channels. When YN-560 IV and YN560-TX used as transmitter, it can realize remote control and parameter settings. •It can be triggered through the flash mounted on the camera, 2.4G wirless triggering system, S1 and S2 pre flash cancel mode. Features: a, TX Master Flash mode: When you set up YN-560IV as TX mode, it can be used as a flash controller transmitter, it can trigger YN-560 IV ( RX mode )and YN-560 III ( RX mode ), and also can be used with RF-602, RF-603 II, RF-605 together. b, RX Slave Mode: When you set up YN-560IV as RX mode, you can use it with YN560-TX flash controller, and RF-602, RF-603 II, RF-605 single transceiver. c, Manual mode d, Multi mode e, S1 / S2 mode --- You should use those two modes off camera f, Power saving mode g, Overheating Protection h, Manually set and zooming position g, PC Synchronous Port Package Including: •1 x YN-560 IV Flash Speedlite •1 x Protecting bag •1 x Original box •1 x Manual in Chinese and English