These are a couple of mounting stands for a Blue Yeti USB microphone. There's a hole at the base to accept and hold the head of a 1/4-20 bolt for mounting to almost anything. A 1/4-20 wingnut or brass knurled nut makes it easy to tighten by hand.
There are 2 variants, and in my application (attached to a 2-segment wooden extension arm) the base of the mount is at the bottom. However, the holders could be mounted upward, downward or at any angle:
- The short one works for holding the mic right-side up - The longer one works for mounting the mic upside-down (full 360 degree rotation)
Just drill a 1/4" hole in the surface you're mounting to, and use a 1/4-20 bolt long enough to go through both the mount and the material underneath.
FreeCad source is included so you can modify to your specific situation.