The hook fits snug on the horizontal side rails of the IVAR shelving units from IKEA.

• Can be attached with or without a shelf mounted on the other side.
• Fits snug to avoid accidental detaching
• No mounting hardware requierd
• Very strong when printed solid (>5 perimeters)
• No supports needed

Note: some older versions of the IVAR shelves have thinner side rails, the hooks won't have a snug fit on these. (worked on recently bought shelves, but not on a set from before 2000)