Replacement crush washer for your drain plug, these are extremely handy to have around.  Avoid any leaks or issues when changing your oil.  Size - M12 

Fits many pitbikes such as:

Z50

XR50

XR70

CRF50

CRF70

XR80

XR100

Grom 125

Z125 Pro

KLX110

DRZ110

CRF110

TTR125

CRF125F

CRF150F

KLX140

Any many many more pitbikes and pitbike engines