The Nikon WG-AS3 Water Guard is designed to maintain the D700's high level of dust and water protection, when used in combination with the SB-900 Speedlight flash unit. The WG-AS3 clips onto the flash unit's foot, creating a shield against dust and water.
This little piece of plastic can save your $ camera.It fits snugly over the flash shoe to prevent water from entering the camera through the flash mount.Useful in the rain or when photographing near water sports where there is a possibility of splashing.While the descriptions states it is for the Nikon D-700 and SB-900 combination, it fits the D-800 and SB-910 with no problem.
I only bought this item to see if it could resolve the flash misfiring issue the d700 experiences. It indeed works and reduces movement between the camera and the flash, which is most likely the root cause of the problem to begin with. Also I have the SB700, so yes it works with other speedlites if you were wondering. A little pricey for a piece of rubber but definitely worth it for solving this annoying bug!