(-6AN (20 feet long)) Requires use of Swivel Seal, Auto-Fit, or Auto-Mate Hose Ends.Army/Navy (AN) Sizing...-3AN = 3/16" Hose-4AN = 4/16" = 1/4" Hose-6AN = 6/16" = 3/8" Hose-8AN = 8/16" = 1/2" Hoseetc....So you take your AN size and divide it by 16...this will give you your hose diameter in inches!