Andoer 16 Channel Wireless Remote Flash Trigger Set 1 Transmitter + 2 Receivers + 1 Sync Cord for Canon Nikon Pentax Olympus Sigma Sunpak Vivitar Neewer YOUNGNUO Speedlite This set consists of a signal sender and two receiver trigger. Globally univeral 433Mhz frequency, 16 isolated channels to suit for specific shooting environments. Transmitting distance up to 30M, no limits with directions or angles. Comes with a PC sync cord for cameras without hot shoe socket. Work with flash units using universal hot shoe like Canon, Nikon, Sigma, Olympus, Pentax (except Minolta SONY, for they use a special hot shoe).