These shelves were just what I needed. Roof cabinets are installed in our campers. The installation didn't take long at all. Since RV cabinets are very cheap to make, I glued/clipped some small blocks behind the mounting plate (because they were attached to the front panel, not the flat side). A little trick I learned along the way. I opened the top door and stuck a small carpenter's square under the door and clamped it so it stayed at the 90 degree mark while I installed the bracket. One spacer is sufficient for each cabinet door. Will definitely buy again.