This is an excellent accessory to have for sharpening knives. I have already used it on two of my most commonly carried blades and they both cut like they were brand new. The only reason I am giving this 4 instead of 5 stars is concerns around build quality. While sharpening, the top of the angle guide popped right off. It looks like is is assembled as two separate pieces, which tracks given the complexity of the design, but it was just pushed into place without any other effort made to ensure that is remains secure. Not a huge deal, and easy enough diy fix, but maybe this can be some food for thought with the next batch or future iterations of this product.