The special urea liquid (DEF) for diesel engine can play its role only when the concentration is 32.5%. Using portable digital urea concentration meter and refractometer PAL-Urea, keeping proper concentration can ensure the function of urea liquid. Portable digital urea concentration meter refractometer/vehicle urea concentration meter/DEF concentration meter PAL-Urea is light and small, and the measurement method is simple. The concentration of the sample can be obtained by pressing the start key for 3 seconds. Its power supply is 2 AAA batteries, portable digital display urea concentration meter refractometer/vehicle urea concentration meter/DEF concentration meter PAL-Urea, which can measure about 11,000 times. PAL-Urea urea concentration meter, vehicle urea concentration meter and DEF concentration meter have automatic temperature compensation function and waterproof function IP65.