Comments about Sto-Fen Sto-Fen Omni-Bounce for the Nikon SB-900 Flash:
SB900 has its own diffuser and sensors to recognize when it is attached and automatically adjust the output. So, when you use this, it will defeat that function. That's one caveat. But for general use, as with SB800 and SB600, this brand diffuser is good.
Comments about Sto-Fen Sto-Fen Omni-Bounce for the Nikon SB-900 Flash:
Have been using this product for years on every flash I own.
The results are great.