High quality silver upper coolant housing with filler and 1.25" hose fitting for K20A/2/3 K20Z1 Applications: K20AK20A2K20A3K20Z1K24A1 Note: Does not fit PRB manifold and throttle body with cruise control. We have been involved in purchases with large turbo settings. The integrated filler now cleans more room for large turbo setups. The filler neck extends from the top of the case and can be used to move the radiator cap to the upper part of the engine. The new location is the highest point of the cooling system and allows pockets of air to escape easily during the coolant bleeding process. The filler neck is also available with a standard 1.25" hose or in 12AN and 16AN sizes and is designed for use with the OEM for Honda Civic 92-00 radiator cap. The upper coolant housing fits our swivel neck thermostat and our off Plate water pump block. All these parts allow many options for custom and racing engine cooling setups. Important: