Box is worn but unit never used. Was in storage. With the Cactus Wireless Flash Trigger System V4, you can place multiple flashes at various angles and distances from your subject. This is particularly useful for portrait and product photography. Each receiver works with one flash. You can use as many receivers as you wish, all receiving their signal from one transmitter. Simply attach the hot shoe of the external flash to that of the receiver, or use the flash connection cable. Most importantly, without the need to connect the flash to your camera by hot shoe or cable, you can move the flash to anywhere that produces the best lighting on your subject. With the flexibility the new Cactus V4 triggers provide, the possibilities are endless!