This 1-5/8 inch long tube header is designed for 1999-2000 Mazda Miata MX-5 (NB) with 1.8L engines and a manual transmission. They are hand welded from 18-gauge 304 stainless steel and use a 3/8 inch flange to prevent warping. The precision-engineered tube geometry offers excellent fit, simple installation and maximum performance.