Clamp hooks for F clamps. Print with a strong filament, PETG etc., use a few more perimeters than 2, decent infill 33% or more. Sized for #10 wood screws, 1 ¼ or 1 ½  inches long. A layer of foam tape on top keeps clamps in place when mounted to a swinging cupboard door. Don't over tighten the screws or you will break the model. The angled side goes up.