I will have to give credit to Yakima for developing a locking system that can be used on pretty much any of their accessories. One side fits but the other side is almost an oval shape. Definitely some of the most comfortable sandals Ive had. Ojalá Amazon tomara medidas para que estos incidentes no ocurran. but when you open the lid, it?s so stiff but not tight enough. I didnt end up keeping these but wanted to, I have square feet and now realize that I need to get square toe shoes. This is perhaps the most important part of putting this unit together. The last step, at the bottom, can be a mess as it seems to be a bit shorter and can cause a person to trip in the dark. These are nice, seem sturdy. Exactly what was needed for the more readily used spices.