Smith Victor introduces the lowest cost radio triggering system available for electronic flash units. This 4 channel system is designed for use with both portable off-camera flashes and studio strobes. This unique accessory gives you reliable radio technology to trigger strobes up to a distance of 150 feet without sync cords or optical slaves. Improve your digital images by eliminating sync cord line noise. Easy To Use: There is no time consuming program or setup procedure. Simply slide the radio transmitter into the cameras hot shoe. Plug the receiver into the flash unit sync outlet and you are ready to shoot. The receiver can be attached to the strobe or light stand with hook and loop strips. The Smith Victor radio triggering system is for use with electronic flash. units having 1/4 phono plug and mini sync outlets. Multi Light Triggering: Using this amazing system at weddings or public events means you can set up individual or multiple flashes and never worry about another photoprapher's triggering your lights. For a fully encrypted multi-light system, one receiver is required for each light.