I have a few of these, as I purchased it to go with my R09 recorder.
It is 1/4 threaded and works great. It's very solidly built, and I have used it with my Zoom H2, Zoom H4, Marantz PMD620, and Edirol R09. Simply love the ball head.
I do video and use a simple mobile setup so I can mic the speakers and crowd, while sending a wireless signal to my camera as well as record main audio to my recorders. This is my small setup. if I am micing a band or recital/play, then I use my Edirol R4 to record via (4) external mics of mics and board feed.
I actually use a mic and and attach my wireless handheld to the mic holder and use a clamp from Windtech to attach to the shaft of the mic stand. Then I attach the OP-R09M to the clamp and adjust as necessary.
Here are some pics on my "Tools of the Trade" blog. Scroll down to the bottom of the age to see. (BTW, this is an old setup, as I said I now mainly use just a wireless handheld and the internal mics on my recorders).
http://lvptools.blogspot.com/