Made from 6061-T6 billet aluminum, comes with size 217 o-ring, which you can get at any local hardware store. O-ring fit is snug and doesn’t fall off. Cap features knurling for finger grip, but you can also use a 10mm hex key if needed. Made in USA.  Super trick! 

Fits:

• KLX110 OEM Side Cover
• Takegawa KLX110 Side Cover