All MAGURA brakes use low-viscosity mineral oil (Royal Blood) as hydraulic medium. Contrary to DOT brake liquid it doesn't irritate human skin or damage the paint on your frame. Biggest asset: It does not absorb water and actually lubricates the whole system. Regular bleeding of old brake liquid is therefore not necessary! 5 Years leak-proof warranty by using MAGURA Royal Blood. Please pay attention to the safety instructions on the packaging working with Royal Blood. For all MAGURA disc and rim brakes.