MCS-931600 - H-D #3; standard heat range. M18 X 1.5 threaded. 1/2" (12.7mm) short reach. Used with a 24mm spark plug socket. This D16 (H-D #3) is the standard recommended spark plug for regular riding. For extensive high speed riding; like extended highway use; a rang

Fitment:
750(45")/1200(74")/1340(80") Side Valve (Flatheads); 36-47 Knucklehead (61/74") (OHV) models (NU)