Firstly, the containers are very well made. As someone who has been working with plastic for 15 years, these things strike me. They are thick enough not to deform when ejected from the mold. It is important for them that they hang flush on your perforated board. The best thing about them is the hangers. I originally put them on containers before putting them on a perforated board, but found that they should be put on a board first. I love this facility! The way they fit into the groove on the back gives you the freedom to choose where to hang them. I will for sure be ordering more of these. Thanks to the manufacturer and seller. Eric