A lot of woodwork depends on joining parts at right angles. If things don't match up even slightly, you'll almost certainly have trouble putting things back together later. I have used them for closet drawers and they work very well. You don't need these clips on every corner. One or two of these will do for the simplest "glues" to ensure everything is even. Clamping angles can be used both inside and outside. They're probably most useful for medium or large sized boxes, but you can also attach them to the outside of a small box. The squares are thick anodized aluminum. In general, the "fit and finish" of the aluminum parts is very good and they should be strong. There aren't many things that can break or go wrong. They look very much like a product from an American company that seems to specialize in red anodized aluminum. These squares are slightly smaller - 7/8 inches, 5 1/2 inches long and 5/8 inches thick - than the "famous brands" which are 1 1/4 inches wide, 6 3/4 inches long and 3 inches thick . /4 in. The aluminum "legs" on these clips are also smaller than the big brands and smaller than some other "fake" I've seen. The main problem with them is that the L-shaped bars don't bend 90 degrees in the clamps. The angle is a little more obtuse. The consequence of this is that the legs of the clamps do not rest directly on the workpiece and therefore do not hold the corner brackets in place. It is a pity. You come close to a good product.