Heil Sound RS-1 Riser Mount

I have the Heil Riser and use it with the Rode PSA1 Studio Arm. It fits perfectly. The hole is 0.5 inches in diameter, is slightly less than 1.0 deep. There is a stop at the bottom of the risers mounting hole to prevent the stub from going all the way through. The PSA1 mounting stub rests nicely in the riser and will rotate with some gentle pressure due to friction. There is a nice brass bushing and a locking screw in the riser. Very well made and sturdy. I'm not sure if other brands will fit as nicely, but the Rode arm works very well with this riser.