A cover for a cassette (Shimano 11-32 in my case) on a bike trainer. I found a lot of them but most of them are quite weak. This model has got 2mm walls and the handle fits the design. It also falls entirely over the cassette so it is fully protected.
I printed this in (Prusa Orange) PETG with a 0.3mm layer height and snug supports. Supports are only required for the handle and the part around the axle.
The author marked this model as their own original creation.