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Call For Competitive Prices! C&S is a full-service Earl's Performance Products dealer. Most sizes are in stock. Let our tech guys design a winning fuel system for you. The charts below will help you determine your AN & NPT size needs.

“AN” THREAD SIZES AN (Army-Navy) Sizes were established by the Aerospace industry years ago and were designated O.D. of the rigid metal tube that each size fitting is used with. (The chart to the right will clarify this point.) The numbers assigned equate to the O.D. (outside diameters) of the tubing in 1/16”. Since tubing and hoses are to be found with assorted wall thicknesses, we can now understand that the designated size number does not necessarily tell you how large the inside diameter will be. (For example, the inside diameter of an Earl’s size 6 hose end is nearly as large as the inside diameter of some manufacturers’ -8 hose ends.)

Each AN size number has its own standard thread size which can be seen in column three of the chart. Again, these are the same thread sizes that have been used in aircraft and industrial applications for many years.

“NPT” THREAD SIZES Some of the most popular adapter fittings shown in their catalog are AN to NPT adapters. While many variations are offered, column four in the chart shows which AN size corresponds to each NPT size when inside diameters (flow dimensions) are considered.
All Earl’s Swivel-Seal hose ends are designed to provide little or no restriction when used with the corresponding AN fitting size. We also offer a number of Metric and British Standard Pipe threads to AN fitting adapters.