MCS-509820 - NPT threads are ''self sealing'' since they are slightly tapered; the diameter slowly becomes bigger towards to top. - 10.1mm is the approx. diameter of this plug in the middle of the plug; including the thread itself. Note: For easier identification of

Fitment:
Fork slider drain plug: 49-E77 FL(NU) Crankcase drain plug: 77-21 XL; 08-12(NU)XR1200 (2 used) Transmission: 01-16 Dyna; FLT Oil pump: 68-99 B.T. Oil tank & transm.: 00-16 Softail Primary: 79-84(NU)FLT; 82-84(NU)FXR; 07-16 Softail; Dyna; FLT