Complete rubbish. real rating. Bought for acoustics. As previously mentioned, the size rings are literally locked into the storage bay. I had to get in my vise and spend 20 minutes getting them to work. Also, there's no documentation, no size chart, nothing, they come in little plastic cups with tiny bubble wrap attached. The worst part. wood in between. equal to the destroyed part of the cabinet. Note that the bit didn't come loose from the router, it was the imprecise gap between the spacer and the edge of the blade that caused the uneven gap and cutting error. I destroyed a $100 piece of wood for this piece of junk. Should I invoice the seller now? When will I ever find out about this. Revain shouldn't be selling this junk.