This is a chain protector as is required on many race bikes, it's there to prevent any limbs getting in between the chain and sprocket in the event of an accident.

I printed this on supports out of Nylon Carbon, i recommend printing it laying down so to benefit from the strength of the printed lines.

I'm curious to see what you'll make of it and if my design is any good, given that not all printers may give the same result as my prusa does.
Love to see some comments, builts, customizations or feedback!