HuguesP submitted a new resource: C-Beam Rail Cover - A 3d Printed Cover that fit perfectly over the C-Beam Slots. Read more about this resource...
Really nice 3D print, well done. As an alternitive, I have used the Slot Covers from the OpenBuilds part store on both C-Beam and V-Slot as they are designed to fit in both of those applications. Slot Cover / Panel Holder