An advanced new design, the MAGNA-FLOW incorporates high-grade neodymium magnets in a unique bipolar, design, sold as a set, it can be applied on fuel line sizes from 1/4" to at least 4" in diameter. Large pipe sizes will require multiple units. The magnets should be mounted on the fuel intake line as close to the engine as possible. MONEY SENSE - Most people drive 20,000 miles per year, on average. At an average of 20 miles per gallon you are using 1000 gallons of fuel per year. At $ 2.50 per gallon that equals $2500.00 per year. If you were to install a Magna-Flow fuel device priced at $69.00 you can save up to 10% and more in fuel, that equals $ 250.00 per year in savings. You save $181.00 in fuel costs in year one and $250.00 every year thereafter. Contact us for more information (we will send you docs by email if desired) on: Testimonials Technical Information Installation Instructions Emissions tests Test Data Federal Technology Alerts Warranty program International Shipping Suggested retail price: $59.00 Contact us for international shipping options