In a message dated 11/20/11 16 58 48, asajay at asajay.com writes: > Can someone point me to a good description of the AN Standard with > regard to fuel line sizing? > BTW, the numbering of AN sizes is not random or coincidental. The AN number describes the hose size, in 16ths of an inch. Thus AN3 is 3/16, AN4 is 4/16 (a.k.a. 1/4) etc. Mike