One Trigger Two Universal Speedlight Trigger Features: 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. Receiver trigger adopts dry battery for supply, the highest synchronous speed can reach 1/250sec. 1/4″ nut design to be connected with tripod for stable flashlight. Receiver powered by 2 * AAA batteries(not included). Comes with a PC sync cord for cameras without hot shoe socket. Work with flash units using universal hot shoe like , Nikon, Sigma, Olympus, Pentax (except Minolta SONY, for they use a special hot shoe).