The heart of the Shaw System is the Multifunction Head Unit (MFHU). To simplify design, the MFHU contains integrated level and temperature, and fluid quality (concentration) sensors . By using ultrasonic sensing technology the level sensor eliminates the problems normally associated with mechanical designs. Outputs from all sensors are fully compatible with major dosing units available today in analog or CANBUS output. Included in the MFHU is an engine coolant powered heater to thaw or prevent freezing of DEF in conditions below 12 F (-11 C). The heater is designed for optimal performance to meet OEM and governmental regulations. Electrical heating is also available for special applications. In order to meet reduced Nitrogen Oxides (NOx) emission levels, many diesel engine manufacturers have turned to Selective Catalytic Reduction (SCR) as the technology of choice. Storage , monitoring, and transfer of diesel exhaust fluid (DEF) is best handled with a single source system solution. Optional items such as remote fill adapters and vents, lockable caps, coolant control valves, electrically heated suction, return, and pressure hoses, and mounting brackets are available to complete the DEF reservoir system.