Snap on bed rail covers to eliminate debris from collecting in the bed rail mount area and keep filament particles from getting into the drive screws. There are other models out there that don't cover the entire bed rail, this made no sense to create a dumpster for filament to collect and were attached using bed mounting hardware. These will mount without having to loosen any hardware that could lead to bed leveling issues and other assorted catastrophes. Be mindful of the rear cover may fit differently than my printer due to wire routing, feel free to modify if needed. These covers do not interfere with bed movement.