For some bikes without a front derailleur (single to nine back gears) the chain can come off easily. This cover prevents that from happening. It is designed so it fits a standard (35 mm) seat post and 200 mm frontal chain ring.
Designed originally for a Bafang MTB rear hub e-bike (Biltema Yosemite EX-TRAIL)
The author marked this model as their own original creation. Imported from Thingiverse.