This product corresponds fully to the description. Easy to install if you take your time and know what you are doing. I installed these spacers on a 20 year old steel floor ladder. One of the old racks had lost its load and the remaining rack would not lift the ladder. I started with 60 kilos. Strive and they were too weak to do the job. I started moving to 80 pounds. models, but opted for 100 LB racks instead. They will raise the ladder, but they are about 1/2 inch close to closing the door. For now I'm thinking I'll try attaching some magnets to keep the door closed and maybe upgrade to a heavier rack in the future. The initial information that came with this build was that the total shipping weight was only 78 pounds. I figured 2-60lb racks would be ok. Not right. Like I said, 100 pound racks hardly work. There is no problem with the shelf. I just have to find the right model.