[Michael C Henry]

AN is for tubing and fittings with 16 = 1". pipe is measured by the inside diameter opening and tubing is the outside diameter of the tube itself.#3 = 3/16" , #4 = 1/4",#5= 5/16", #6=3/8", #8=1/2" #10=5/8", #12= 3/4",#14=7/8", and #16=1", and so on.