Kirk FX-1B Flash X-Tender, Fits the Nikon SB-80 & SB 80dx

Whether you use a flash as main light or a fill, the Kirk FX-1B Flash Extender is a must with lenses 300 mm or longer. This unit weighs less than 3 ounces and folds flat for storage. The Flash X-Tender increases your flash output by a minimum of 2 full stops (3 stops from a flash's 50 mm setting).