FCS II Matt Biolos Reactor PC Carbon Thruster FinsMatt Mayhem Bioloss MB shaper fin. Reliable on the open face, or in the pocket. Overview Matt Mayhem Bioloss signature template delivers a lively combination of drive, hold and manoeuvrability. This versatile fin will feel reliable out on the open face or tight in the pocket. Ideal Conditions A wide range of conditions, particularly good in critical overhead waves. Board Types Designed to fit the FCS II Fin System. Performance shortboards and hybrid