This is a very well built speed-ring, and it absolutely does the trick, but the flange opening that mounts to the AB/Einstein is about 2mm too small in diameter. This prevents the mounting claws/springs on the flash unit from opening up all the way, and thereby does not hold the speed ring in place quite as snuggly as intended.
This is NOT A PROBLEM under about 95% of scenarios, but does create the occasional issue with heavier modifiers at steep angles not staying in place.
I confirmed the size issue by comparing it to the speed ring that comes from Paul C Buff (i have several Paul C Buff strip boxes); the inner flange on this one (the one that mounts to the flash unit) actually fits (ever so slightly) inside the inner flange of the Paul C Buff speed ring.
I will still continue to buy these speed rings, as should you, but I hope one day they adjust their design. If they do, I'll buy all new speed rings from them just for the added confidence.