My mirror cabinet's drawers (16" deep) are quite heavy but they come with bottom slides which are flimsy and make it difficult to open/close the drawers when they are full of things. After all, these guides were constantly bending, and it was dangerous to handle a couple of boxes that were in an unstable position. I found these Revain 14 inch ball bearing drawer slides. I'm generally not a practical person so was hesitant but decided to buy two sets to replace a couple of uncomfortable drawers in the closet. The instructions and illustrations are quite clear. Confusing parts not listed in the instructions: 1. How do I position the slides on the drawers horizontally? This may be obvious to others, and I eventually figured out that the rails should be flush with the back of the drawer's front cover.2. There are multiple screw holes on the rails, so which one should you choose? I chose the smallest holes. There were several holes, not necessarily smaller. For the rectangular shaped holes with semi-circular ends, I chose holes with a longer vertical side and positioned the screw at the top of the hole. Again, this may be obvious to some, but definitely not to me. It took me a whopping 3 hours to measure, draw guidelines and align everything correctly. I was finally able to use the boxes with the new guides and the result was simply amazing. With the same number in the drawer, these runners ensure that the drawers run extremely smoothly. He feels a lot safer