Buy Offer - Rubber Washers

I am Seeking a Company that Can Supply Me with the Rubber Washers to Fit the Cap On the Gasoline Cans I Make. I am Not a Rubber Expert So I Do Not Know What Type of Rubber is Needed But It Must Not Swell or Rot When It is Soaked in Gasoline. the Measurements of the Washer is ---[ Outside of Washer 43 Mm] [ Inside Hole 24 Mm ] [thickness of Rubber 4.5 Mm ]
do You have such a Washer? I Need 600 to Start with and Perhaps More Later.