What else can I say, for the price it's extremely good quality. I was amazed when I received the 8 inch hole saw and it was the right shot. Just shocked what a good deal this is.
Will not fit my new Bosch SDS-Plus bit no matter how hard I try. Other SDS-Plus bits will fit with no effort. Not sure it's a defect or misleading advertising. Also, the locking mechanism doesn't work well, the locking pins barely fit in the holes on my hole saw (just tilting it unlocks it.) I bought a similar mandrel from a big store which closes safe and doesn't have this problem at all. Overall it looks like either bad design/manufacturing or bad quality control.