This is clip to keep the twist rod steady on window blinds (in our case from either wind or a cat that believes it is their right to rattle the thing in the middle of the night). This was designed to fit the clear plastic rods that are about 7mm in diameter and affixes to the wall with 3M Command Strips (poster sized).
Thought this was made from scratch, inspiration from: https://www.printables.com/model/304202-blind-rod-clip-stay
The author marked this model as their own original creation.