Don't kow the exact answer to your question but I bought the AT8415 - http://www.sweetwater.com/store/detail/AT8415/ and it's a perfect fit

The Royer don't come with a shockmount. I bought the RSM 1 shockmount with my R122 and it did not come with an adapter. Had to use a spare one...

Thomas

No, I bought the shockmount separately but I can't find an adapter. Thought the spare from my Sennheiser MD421 would work but it didn't. What kind of adapter does it need to fit on a mic stand? Do they have em at Guitar Center?

bump-sorry. What kind of adapter is needed for the RSM-1 shockmount?

Just to update this thread,
I have a pair of Royer R-122 and ordered the RSM-1 Microphone Shock Mounts. If you are in the market for these mics, I would definitely invest in these mounts. They fit a stand perfectly and are very well made.

The RSM-1 was designed for maximum shock protection, durability, ease of use and versatility. Not to mention that it's got a Royer logo and looks sharp. It's made of high-tech materials that will hold up for many years, and it doesn't use elastic bands that can stretch out over time.