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 power 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 Canon, Nikon, Sigma, Olympus, Pentax (except Minolta SONY, for they use a special hot shoe). Note: This trigger do not support TTL function. Specifications: Power of the signal transmitter: 23A 12V mini battery (included) Power of the receiver (AC): 2 * 1.5V AAA Battery (not included) Outdoor working distance: max. 30m / 90feet (open area, no fraise) Indoor operating distance: max. 25m / 75feet Channel: 16 channels Frequency: 433Mhz Synchronous speed: Max. 1/250sec Color: black Material: Metal + plastic Package size: approx. 11.5 * 9 * 4cm / 4.5 * 3.5 * 1.6in Package weight: 111g / 3.91oz Package Lists: 1 * 16-channel Transmitter 2 * 16-channel Receivers 1 * PC Sync Cord (2.5mm to PC) 1 * User Manual (English) Note: This item only includes the trigger set and sync cord