Hope mono m4 complete caliperthe redesigned mono m4 disc brake caliper has been slightly modified but is still a one piece caliper which has been machined from a solid billet of aluminium to reduce weight but also to make it as rigid as possible improving lever feel braking performance all calipers are now 974 use different brackets for different mounts caliper pistons are still made from phenolic to isolate the caliper from heat generated in the pads caliper is now a natural aluminium si