Magura Two Piston Caliper Rings Magura's awesome new two-piston design means powerful braking, but it doesn't mean maintenance isn't required to keep the killer calipers running properly. This Two-Piston Caliper Ring set replaces original rings on Magura's caliper assembly. Features Two-piston design replaces standard piston rings on Magura calipers | Magura | Two Piston Caliper Rings Purple, Red, Neon Pink