Not only does the SK-6 enable you to use the camera mountable SB-80DX as a grip type flash, ia also offers you remote flash capabilty.
Used as an external power source, in combination with the Speedlight's own power source, the SK-6 reduces minimum recycling time by about halfdoubles the total number of flashes and available. It accepts 6 1.5V LR6 (AA-size alkaline), 1.2V KR-AA (AA size NiCd) or 1.5V FR^ (AA size lithium) batteries.
Warranty
Reviews Nikon SK-6 Power Bracket for Flash