Kirk FX-2 Flash X-Tender, Fits Canon 540 EZ & 550 EX, Nikon SB-25 & SB-26 and Sigma EF 500 Flashes

Whether you use a flash as main light or a fill, the Flash FX-2 x-Tender 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). The FX-2 fits the Canon 540 EZ & 550 Ex, the Nikon SB-25 & SB-26 and the Sigma EF 500. The measurement between the ears of an FX-2 is 1-3/4".