Shimano zee disc brake caliper m640 calipers with ceramic 4 piston calipers system stiffness is tuned using shimanos high power hose and shorter lever blade while ergonomics are perfected with a new pivot location and dimpled surface ice tech brake pad and rotor options reduce heat in the system and maintain performance on the longest descents shimano introduces zee a new line of gravity components that are an ideal starting point for aggressive riders and racers zee is the gateway gravity