Wilwood Caliper-BNSL4R 1.75in Pistons 1.25in DiscThe Superlite caliper series has set the standard for many years in short track, late model, modified and open wheel competition. It has also enjoyed prominence in a variety of road race, off road, rally and sport driving applications. Starting at 4. 40 pounds, the Forged Billet Superlite (FSL) is the newest innovation to this series from Wilwood. New and adaptive technologies have been applied providing substantial improvements in strength, fluid