These -6 AN hose-end fittings from Earl's Performance have a 90-degreee bend and are the correct size for the 3/8-inch fuel line used on our project. The AN stands for Army Navy and these fittings were developed by the military to make very reliable connections in both flexible hosing and in rigid tubing. AN sizes range from -2 to -32. Every step equates to the outside diameter of the tubing in increments of 1/16-inch. Hence, a -4 AN size would be equal to 1/4-inch OD tube (4 x 1/16 = 1/4). The AN system does not specify the inside diameter, as tubing wall thicknesses vary. AN fittings are a flared fitting and use a 37-degree flare to form a metal-metal seal. Don't try to use an AN fitting with a standard 45-degree SAE flare fitting or line, as leaks will be your only result. The following chart should help you determine which AN size you need for your application.