2.5" 63.5mm ID Aluminum Alloy Weld On Filler Neck and Cap Oil, Fuel, Water Tank Ideal for custom tanks, splash bowls, etc. Feature: Material: 6061-T6 Aluminum Alloy ID Size: ID Size: 1" (25.4mm) / 1.5" (38.1mm) / 2" (50.8mm) / 2.5" (63.5mm) /3" (76.2mm) Cap Color: Black Neck Color: Pure Natural for perfect weld. Packaged: 1pc 1" (25.4mm) / 1.5" (38.1mm) / 2" (50.8mm) / 2.5" (63.5mm) / 3" (76.2mm) Aluminum Alloy Weld On Filler Neck Cap Note: All pictures are actual shooting, slight color size difference is shown in the pictures.