Features: This product is made from high-strength aerospace aluminum. It is designed to maximize resistance to breakage, providing improved durability compared to the OEM fitting. The coolant flow path through the center of the fitting is optimized to enhance coolant flow. Additionally, the surface area of the coolant flow path is larger than that of OEM components, further improving cooling performance. This hose connects the coolant thermostat housing to the front of the head. The plastic fitting on this hose is a known weak point in the coolant system, prone to cracking and leaking. This aluminum fitting provides a durable, long-lasting solution that will not crack, wear out, or leak. It is a direct replacement for the stock plastic fitting with no modifications required. Made from high-quality aluminum alloy, it is durable and wear-resistant. The fitting has a smooth internal design with no sharp corners, allowing coolant to flow without restriction. Built to factory original equipment specifications to ensure a proper fit. Installation is straightforward: remove the hose end from the plastic fitting, remove the old fitting from the head, install the new fitting into the head, then reattach the hose and hose clamp. Specifications: Material: Aluminum Alloy Length: Approx. 4.3cm / 1.69 inches Color: Silver / Red / Black / Blue Fits: 3 Series N54 335i 335 OEM Part Numbers: 11537541992, 11537544638 Package Includes: 1 x Water Hose Fitting Note: 1. Please allow 1–2 cm error due to manual measurement. Ensure you are comfortable with this before ordering. 2. Due to differences in monitor displays, the actual color may vary slightly from the image. Thank you for your understanding.