Modulus hulls, in a nutshell, are Carbonlite 2000 on the exterior, and composite (Fiberglass/Kevlar) on the interior. Therefore they may be repaired with methods that would work on either Carbonlite kayaks (for the deck and exterior of the hull) or Composite kayaks (for the interior of the hull). Modulus Extreme kayaks are a hybrid of Carbonlite and Kevlar on both the deck and hull.