AN Fitting Size Guide:

The AN numbers refer to the tubing OD in sixteenths of an inch.

AN SIZE

MALE THREAD SIZE

TUBE SIZE (NOMINAL OD)
HOSE ID
4AN 7/16"-20 1/4" 0.22"
6AN 9/16"-18 3/8" 0.34"
8AN 3/4"-16 1/2" 0.44"
10AN 7/8"-14 5/8" 0.56"
12AN 1 1/16"-12 3/4" 0.69"