Standard Size: AN-6 (5/16") Black Nylon CPE Made Fuel Line:ID: 8 mm (0.315"),OD: 11 mm (0.433") AN-8 (13/32") Black Nylon CPE Made Fuel Line: ID: 9.7mm (0.382"),OD: 12.8mm (0.504") AN-10 (1/2") Black Nylon CPE Made Fuel Line: ID: 12.7mm (0.5''),OD: 15.9mm (0.626'').