I sent this set back immediately after opening it. I will mention that I have never used this to test the quality or functionality of the tools myself. The metal body was fine, but the locking system felt cheap and could fail easily. Once that happens my garage floor will be a mess as the trays in it are like the plastic your oversized chocolate bunnies show up in at Easter. They don't hold the tools in place and got scattered when opened. In trying to put them in place, I noticed that the size markings on the instruments themselves are difficult to read, sometimes crooked, and sometimes barely visible. Some just didn't show up at all. The size labels on the trays were everywhere (some on top, some on bottom, some overlapping other tool spaces). The sizes appear to be sorted by physical size, forming a grouping of SAE, metric, coarse, fine and whatever. I felt like everything in one area makes sense and it just hurts to find what you are looking for. The trays happily fold when taken out of the case and as they are stacked you will need to remove at least one from time to time to get what you need.