Originally Posted by maranen

-At the lower end of the seat-tube there is a plastic cone attached with a rubber band to a small wooden ball at other end of the tube under the seat. This eliminates dirt entering inside the frame tube when riding in foul weather, and dirt getting between the seat-tube and frame when folded and then unfolded again. The rubber band runs inside the seat-tube and it’s length is such that the cone is always pressed against the frame tube/unfolded or against the seat-tube/folded.