This Osco 3320 Exhaust 3" Riser Spacer fits Mercruiser Mercury and is a great addition to your boat's sterndrive motor and component system. It is made by Sierra, a trusted brand in the industry, and is compatible with 18-1908 models.

Below the part numbers two are marked E2 and two are marked E4. Appears they are opposites in regards to threaded pcs on sides. Please specify which style you want.

The spacer is designed to enhance the performance of your engine by providing a smooth and stable exhaust flow. It is easy to install and comes with two other part numbers: 93320A10 and 93320A13. This product is perfect for anyone looking to upgrade their boat's exhaust system and improve their engine's performance.