We Use 3K, 5 Harness Satin Weave Carbon Fiber. This Is the Heaviest, Tightest And Strongest Weave On The Market Giving You 50% More Carbon Fiber Per Ounce. Originally Created For The Aerospace Industry, We Know That We're Giving You The Absolute Best Carbon Fiber. Most Commonly And Readily Available Are The Light Weight Plain Twill Weaves Which Gives You Less Carbon Fiber Per Ounce. At The Same Time, Others May Use Dyed Fiberglass Or May Thicken Their Shells With A Fiberglass Backing Giving It A False Appearance.