Aputure Flash Trigger Trigmaster II 2.4G RECEIVER ONLY for CANON Compatible with all 2.4G Aupture triggers for CANON. Control strobe & speedlight flash. Multiple camera shutter control. 2.4G FSK radio frequency. No flash leakage within 80 meters. Compatible with high voltage flashes. Compatible with all 2.4G Aputure triggers. Bulb mode (long exposure).