All Easystow inflatable boat products share the same air chamber, but with the heavy duty models, the cover is actually extruded as a one piece tube. That means reinforcement is continuous for greater strength with no longitudinal seam to catch or split. The thick coating has good abrasion resistance and since they're reinforced, they can't balloon like cheap fenders. When deflated, they lay flat or folded. Heavy Duty Fenders are only available in blue.