This is a mounting collar for the Switchbot Blind Tilt, which is a handy little device that can open and close blinds. It comes with a little sticky mounting pad that actually does a surprisingly good job of keeping it in place. Mine stayed up well over a year before the constant twisting (that is what it does, after all) worked its pad into ineffectiveness.

At any rate, this replaces the mount and the pad it sticks to with a collar and a replacement mount that the Switchbot Blint Tilt should snap right into. It mounts to the blinds by fitting over the headrail. This means, of course, that you'll need to remove your headrail and measure it quite precisely -- the collar should fit snugly to keep it from sliding around too much, but it doesn't have to be tight.

The OpenSCAD file is included, and the only two parameters are at the top, the depth and height of your headrail. Most headrails tend to be pretty uniform from one end to the other, but they can flex a bit, and you'll probably want to measure it where the mount would go.

I printed this on a Bambu H2D using PLA, but PETG for supports. Since precision is required, I printed it upside-down relative to the orientation of the model with tree supports. I didn't create a version for testing the fit of the ring (you may do so, of course) partly because changing the orientation of printing the part would also change the fit.