Finish Line has two high-performance brake fluids. One is mineral oil-based and the other is a synthetic DOT 5.1 formula (refer to the brake user guide for the type of oil). Both fluids are designed for use in hydraulic disc bike brake systems to provide maximum fluid lifespan and optimal braking performance. Although they are 100% compatible with DOT 3 and DOT 4 fluids, Finish Line’s DOT 5.1 performance specifications far exceed them. Both fluids use low-viscosity oils to ensure excellent operation even in very cold conditions.