The JJC Flash Multiplier FX-N910 is ideal for use with telephoto zoom lenses. The multiplier increases the flash's output by two to three f/stops allowing you to shoot from a greater distance and use smaller aperture values. The set is lightweight, making it portable enough to take with you. The set is also quick to assemble. Another great advantage of this Flash Multiplier from JJC is that your flash's battery lasts longer, as the flash does not need to flash as powerfully for high output. So you save on your battery and this reduces the flash's recycle time.