Aluminum nipple by TurboWorks. Purpose: oil system, water system, fuel system. For use with rubber and nylon hoses. External diameter 9.5mm. 7.5mm Suitable for AN6 8.5mm TurboWorks Aluminum nipple hose. Usable for: oil system, water system, fuel system. For use with rubber and nylon hoses. TurboWorks aluminum nipple. Purpose: oil system, water system, fuel system. rubber and nylon.