These clips were created to hold a towel / rag securely on the handle of an oven, fridge, or rack. The inner nub is meant to keep the item from slipping on ridged handles. There are a couple different versions provided but the 4th (towel_holder4.stl) was the most secure in my situation. You can scale them to fit tighter if needed and the variations have to do with the size/position of the inside nubs and the length/angle of the bottom grippers.
Minor auto-generated support was used to hold up the bump on the inside. Printed in ABS with 3 shell layers, 7 top and bottom layers. My infill for these parts was 30% and layer height 0.12mm, feel free to change them to your desired amounts.