Aputure MXII-C Trigmaster II for Canon (Black) Three in One function; Control Studio Strobe Light, Speedlight flash and Camera Shutter 2.4G Radio Frequency: more Stability and Sensitivity; 16 Independent Channels Flashes may be triggered up to 120 meters in an open area, no flash leakage within 80 meters. Awakens most Speedlight's, including Canon, Nikon, Olympus, Pentax, etc. Compatible with High-Voltage Flash. Upgraded Transmitter provides a Longer Battery Life