Part Number: 04L121026F 04L121026A 04L121026AH; Functions: Water temperature controller housing protects the motor and water temperature controller from external damage, ensuring their proper functioning. Material: Specialized materials offer hardness and practicality for long-term use, providing support and effectively reducing friction. Easy Installation: Replace your existing damaged coolant thermostat directly; practical and easy to use, simple installation steps. Design: This thermostat and housing replacement provides a reliable solution for your vehicle's cooling needs. Note: Installation location, typically at the cylinder head coolant outlet, is simple in design and facilitates drainage, maintaining temperature and preventing overheating.