Mechanical two piston disc brake for road levers weight 146g spyre slc 154g spyre per wheelrotor weight 85g 160mmpads tk bp e1011 two piston movement evenly contacts rotors for optimum braking power and modulation robust carbon fiber or alloy actuation arms ramped ball bearings offer smooth pad engagement and precise modulation cable fixing position options optimize performance with 20 or 25 ratio levers integrated cable barrel adjusters roadcc review is worth a good read