This is a protection for the rear brake system for the xiaomi M365.
My wife hurt her leg badly with the xiaomi rear break when it suddenly spin into her leg while she was pushing it on a climbing slope.
This protection was designed to avoid such injuries.
Printed flat with support for the inner holes using ABS.
PLA is OK.
My printer is an Anycubic i3 mega.
Enjoy you M365, be safe.