This round aluminum oil tank is made from 1/8" thick 6061 T6 aluminum-the same aluminum used in the construction of military aircraft. It is tough and looks great as a replacement to the ordinary oil tank that comes with your stock softail. The aluminum helps to remove heat from your engine oil and looks great as well! Oil line fittings are 1/4" NPT. Fill spout uses 1999 and under oil caps. This model is for Harley-Davidson Softails 2000 and up.