3 Receivers PT-04GY Wireless Flash Trigger for Canon Nikon Pentax Olympus Universal hot shoe interface, compatible with Canon, Nikon, Sigma, Olympus, Pentax, etc. Globally univeral 433Mhz frequency, 4 channels. With studio flash interface, can trigger several kinds of studio flashes. Transmitting distance up to 30M, no limits with directions or angles. 1/4 inch nut can be connected with tripod or light holder to make flashlight safe and stable. Speedy frequency regulation, convinient for photographers to shoot. Energy-saving design with 12V 23A battery of transmitter and 2 AAA batteries(not included) of receiver. Comes with a PC sync cord for cameras without hot shoe socket.