SET OF 2 PERFORMANCE SPARK PLUG Harley Davidson XL 1200 C Sportster Custom 2012-2004 * GFRT830BR14ZCYU919 1. Higher HP and torque by up to 3 % 2. increased economy by up to 5% 3. 360 Firing Technology 4. Improved acceleration by up to 15 % 5. 25,000 miles - 40,000 km duration