The EX38 features a 38mm valve and comes with a standard 10psi spring. By combining available 5psi, 7psi, and 10psi springs, you can achieve base boost pressures of 5, 7, 10, 12, 15, 17, and 22psi.Only 93mm tall, shorter than competitors.Tapered inlet flange and larger seat I.D. for smooth exhaust t..