From 20 years of rolling with an 18-inch roller comes this working fixed-width prototype to improve 13 areas in roller frame design and user experience. Unique end-construction features were intentionally omitted in the photo. The materials are less important to the function of the design although light-weight is preferred. The presentation seen here speaks a little about the design. The CROSSBOW design is one of several frame designs and addresses all known annoyances and limitations in current frame designs and adds new features and capabilities. Serious inquiries only.