Lowbrow filler caps fit the maxim 'form follows function'; they are all business. These caps are 1-5/16"-12 thread, and are sized to be a filler cap for either a gas or oil tank. The Buna-N O-ring seal is gas and oil resistant and keeps your fluids contained, leak-free. Lowbrow filler caps fit our steel or aluminum weld-in bungs for custom applications, as well as Mooneyes & British Standard brand oil tanks. This cap is vented and features an O-ring seal. The threads measure 1-5/16"-12. Sold Individually. Made in Ohio, USA.