Mocal flush fit fuel caps are expertly crafted in polished aluminium and are clear anodised for a long lasting, professional look. The cap is sealed with a fuel resistant O-ring and comes supplied with a fitting kit comprising of - stainless steel nuts, bolts and a fibre sealing washer.These large diameter caps are available in 3.5 or 4 inch (the size relates to the removable centre cap) and are available in locking or non-locking versions.Fitting options include:Plain cap with no funnel for mounting directly to the tank.Cap with integral funnel for attaching a flexible fuel filler hose.