They support the rails well but your drawer can't close past the slots so you need to have enough depth in your cabinet for the drawer plus about 2 1/2 inches extra for this one I did bought her and the slides at a local hardware store and after spending about 3 hours installing them everything worked great but the drawer wouldn't close the last 1 1/2 inches or so. Give them back. So be careful. The instructions do NOT state this limitation.