Description:4 Channels Selectable, Wireless control, Easy Operation. Advanced Channel Isolation, Operating In dependently. The trigger life is up to 10 thousand times with 0.01 mA electric current. The receiver's highest synchronous speed up to 1/500 second (according to cameras). 1 receivers for triggering 1 flashlights synchronously, or one flashlight and one studio light. Specification:Material:ABS Size:55x40x30mm Frequency Channel:4 Operating Frequency:FM 433Mhz Outdoor Synchronous Speed (open area):Max 1/500sec Indoor Synchronous Speed:Max 1/250sec Receiver battery type: 12V 23A (Not include package) Maximum operating range: 20ms How to Use Three working options are available: 1. If your camera has no hot shoe for fixing the transmitter, you may connect the transmitter to the camera by the PC Sync Cord provided. 2. Use the receiver on old studio lights with 2.5mm(diameter) hole. 3. Connect the transmitter to the receiver directly. Compatible with for Canon SpeedLite 580EX II, 580EX, 550EX, 540EZ, 520EZ, 430EX/EXII, 430EZ, 420EX, 420EZ, 380EX; for Nikon SpeedLight 900, 800, 600, 28, 27, 26, 25, 24; for Olympus FL-50, FL36; for Pentax AF-540 FGZ, AF-360 FGZ, AF-400 FT, AF-240 FT; for Sigma EF-500 DG Super, EF-500 DG ST, EF-430; for Sunpak Auto 2000DZ, 622 Pro, 433AF, 433D, 383, 355AFm 344D, 333D; for Vivitar 285HV (Older Vivitar 285/283 works only with PC sync); for Other flash models with a trigger voltage of 12V or lower; Work with flash units using universal hot shoe like Nikon, Sigma, Olympus, Pentax (except Minolta SONY as they use a special hot shoe).Package Includes:1PiecexWireless Flash Trigger1Piecex Sync Cable