High-performance replacement 44mm aluminum piston specifically designed for StopTech STR-40 (Trophy Series) and ST-40 forged calipers. This precision-engineered component is ideal for caliper rebuilding to restore optimal hydraulic performance and pedal feel. Features a hard-anodized finish for superior wear resistance and thermal stability under extreme braking conditions. Components included in this series (sold separately or as part of a kit): - Piston: 41.544.0001R (44mm) - Dust Boot: 143.99002 - Pressure Seal: 143.99102 - Rebuild Kit (Single Wheel): 143.99023 Note: This is a single 44mm piston for STR-40/ST-40 series calipers. Please verify your caliper piston sizing before ordering as ST-40 calipers use staggered piston diameters.