Race Car Performance Alloy Vertical Header Tank with Sight Tube Capacity: 1.5 Litre Cap Sold Seperate. This is ideal for all types of car, it is made out of 2mm Alloy and is very light. Size: 200mm x 100mm, Standard Radiator Cap Top, 10mm In, 18mm Out, 8 mm Over Flow Pipe (NO CAP) This unit is designed to fit to a bulk head or some flat surface. Professionally manufactured in Obp Ltd factory by skilled tradesmen in England.