OBX Silver Underdrive Crank Pulley 02-12 Nissan Altima/Sentra 2.5L QR25DE Super Lightweight T-6061 T-6 Aircraft Grade Billet Aluminum Computer CNC Machined For Precision Balance Increased Horsepower And Torque Across Entire RPM Range Dyno-tested And Proven On Race Track, Consistent Horsepower Gain at all Speed levels High Quality Polished & Anodized Finishes