Wmicro Aputure MXII-C Falsh Trigger Transmitter + 2 Receivers for Canon DSRL Camera T3i 600D 550D 5D Mark II Wireless Sync Trigger Remote Shutter with 16 independent channels Wireless synchronous trigger studio flash & flash-top flash&lt;br&gt; 2.4G Radio Frequency: more Stable and Sensitivity. Ultra-fast microchips enable sync speed of 1/250 seconds. Leading Flash distance can up to 120 meters at open area, no misfire within 80m Compatible with High-voltage Flash and TX3C Flash Trigger