Some of the welds on these hole saws were sloppy with bulges on the outside that could bind; a few teeth protruding outward, usually at the saw's weld, causing the saw to move poorly and making an oversized hole; and some of the whole saw bodies were not round. It took me about thirty minutes to grind and sand them down to get them closer to a better approximation of round solid saws. After that I wouldn't trust them for precise sized holes (which they're not designed for anyway) but now they're great for bigger holes. The quick release on the mandrel is handy for large saws. The smaller mandrel does not have a quick release. There are a few extra drill bits included which is nice. They just lie in a box with no particular storage place, which isn't very nice. Inside the box is a vacant spot for the optional 1-3/4" hole saw. What to do with that? " Overall pretty poor production quality control and a box that doesn't match the tools provided and room for a hole saw offers which is not included. Works fine once repaired but why buy a tool kit for it? Need for improvement • Do you eliminate manufacturer errors? Isn't it better not.