Shimano deore m615 disc brake calipertwin piston deore brake caliper providing efficient braking with a minimalist design original shimano parts guarantees that all components work perfectly for optimum performance and maximum safety and longevity featuresfor use with mineral oil which is non corrosive and less hazardous than conventional hydraulic fluidthe one way internal fluid circuit makes bleeding easy while great piston retraction increases pad to rotor clearanceshim less mounting bra