Upgrade your Mercury or Mariner 3 Cylinder Outboard Engine with the Sierra International Block Cover Gaskets. This pack of two gaskets, model number 18-2504-9, ensures a perfect seal, preventing leaks and maintaining optimal engine performance. Made from high-quality materials, these gaskets are designed for durability and reliability, making them an essential component for your engine maintenance. Easy to install, they fit seamlessly, providing peace of mind during your boating adventures. Keep your engine running smoothly with Sierra's trusted quality!