I use this to adapt a 1/4" collet on my CNC router to a 1/8" collet for small routers. Grips 1/8" bits tightly and without slippage. Very good balance, no vibration and clean cuts. Quality product at a very competitive price.
Gives me some extra room on my CNC to remove the clamps with a router. There seems to be almost no beat. (I think my dial gauge reads about 0.005 inches). I only cut wood so that's not a problem. Also, I use 10 packs of cheap 1/8" bits with two flutes that can improve the beat. (Haven't broken any yet.)
This part lasted approximately 30 hours before failing. Torn when changing the bit, immediately twisted the threads. And it's not that I'm over tightening this screw, it's only 11mm so you know you don't have to over tighten it, it's just a very cheap design, don't waste your money.