This Volvo Penta exhaust system includes two penta aluminum manifolds, part numbers 21356423 and 21356421, which are compatible with a variety of sterndrive motors and components. The brand is known for its high-quality products, and this set is no exception. Please note that this item does not come with a warranty. If you're in need of a replacement or upgraded exhaust system for your boat, this Volvo Penta set is a great choice. It's easy to install and will provide optimal performance for your motor. Please email me with any questions. Thank You!