It's junk-in-glass because this pinhole is complete garbage.

Check out the threads on this sucker! I dobut I found this one on a pin, because I can't ever imagine being able to screw it on or off of one. On the front half of the pinhole, there is actually a large spot where the threads spiral downwards to the right - the wrong direction! I suppose the "compensation" that makes the incorrect spiral mathematically possible is the 45 degree thread slope in the rear half!