Wet Marine Exhaust Manifold 3923312 3923313 for Cummins 4B 4BT 4BTA 3.9LWet Marine Exhaust Manifold Feature: 1.Ideal Replacement The exhaust manifold exhausts the exhaust gases produced when the boat is running into the atmosphere while reducing noise. Timely inspection and replacement of a new manifold can greatly improve your driving comfort. This is a perfect replacement that has the same quality as the original unit. 2.High quality and special Built to strict OEM quality standards, the exhaust manifold is made of high