The harness is built around the patented Bionic Core Frame (BCF), which is a semi rigid back support plate; its unique composite material is very stiff yet it allows more flexibility than conventional hard-shells. The Stealth is an evolution on the well-known Majestic & Legend harness. It combines the stiffness of the BCF (Majestic X) with the non-water absorbing inner shell of the Legend harness. Best of both worlds!