neewer 16 channel wireless remote fm flash speedlite radio trigger with 2.5mm pc receiver for flash units with universal hot shoe neewer <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)