1. The typical AN size is referred to as a dash number, as in -6 (and stated as “dash six”). The dash number is equal to the outside diameter of hard tubing in 1⁄16-inch increments. Therefore, a -6 would be equal to 3⁄8-inch tube OD (6x1⁄16=6⁄16=3⁄8). Inside diameter can vary due to wall thickness, but it is generally accepted that tube OD and hose ID are the same for AN hose selection requirements (see sidebar chart at end of story).