BestDealUSA 4 channe Wireless Remote FM Radio flash Speedlite Trigger w/ 2.5mm PC 2 receiver This flash trigger device is control discreteness for camera to trigger hot shoe flashgun synchronously. It's made up of two parts named signal transmitter and receiver. Work through wireless wireless remote signal controlling. The transmitter is consisting of advanced designed circuit and component,and works through sending encoded signal. It comes with 2.5mm sync port,which permits the camera without hot shoe using this flash trigger.So,this flash trigger can work with all camera with stand hot shoe mount and those cameras with 2.5mm mm port.(but not work with Sony flashes) Very low voltage working make sure that high level of safety and no damage to camera. It is very useful when you want to trigger 2 flashes at one time.