<p><b>Specification:</b> <p>Operate frequency: 433MHZ <p>Sync speed: 1/250s <p>Work range: ≤30M <p>Screw mount on receiver: 1/4" <p>Battery for tramsmitter: 23A-12V mini batter (the battery included) <p>Batery for receiver: 2x1.5V AAA battery (the batteries not included) <p><b>Suitable:</b> <p>Canon SpeedLite 580EX II, 580EX, 550EX, 540EZ, 520EZ, 430EX, 430EZ, 420EX, 420EZ, 380EX; <p>Nikon SpeedLight SB-800, SB-600, SB-28, SB-27, SB-26, SB-25, SB-24; <p>Olympus FL-50, FL36; <p>Pentax AF-540 FGZ, AF-360 FGZ, AF-400 FT, AF-240 FT; <p>Sigma EF-500 DG Super, EF-500 DG ST, EF-430; <p>Sunpak Auto 2000DZ, 622 Pro, 433AF, 433D, 383, 355AFm 344D, 333D; <p>Vivitar 285HV (Older Vivitar 285/283 works only with PC sync); <p>Other flash models with a trigger voltage of 12V or lower; <p>Work with flash units using universal hot shoe like Nikon, Sigma, Olympus, Pentax (except Minolta SONY as they use a special hot shoe). <p><b>Package Contents:</b> <p>1x Transmitter (with built-in battery) <p>2x Receiver (AAA Batteries not included) <p>1x PC Sync cord for camera (2.5mm to Male)