Add-on shelving extends the length of your current shelf, requiring less posts and allowing more unique storage configurations. Attach add-ons at a right angle using the included S-Hooks. Design provides extra storage while also saving space Holds up to 800 lbs per shelf, evenly distributed Shelves adjust every 1" along posts Made for indoor use, dry storage only S-Hook 2-Packrequired per extra shelf To securely set or quickly remove shelves, tap their corners with arubber mallet. View ourWire Shelving Size Guideto see actual outer and inner dimensions.