Circular fastening, cylindrical gripper, variable diameter connector, jubilee clip, hose clamp or adjustable radial constriction device that will grip firmly around a cylinder, a rod or pole - typically used to secure a hose to an outlet. Could be incorporated into other models.

The size in the filename of each mesh represents the interior radius of the hoop, when the fastener is printed and slightly open. This will fasten down to ~1mm less than the initial state at max.

Leave a comment or send a message if you'd like me to export some other size. I got about a third of the way to doing this in OpenSCAD before giving up, so it's not user parametrizable as of now.