牛奶專用奶稠計 Hydrometer for milk, in conformity with the former DIN 10290 standard, without thermometer, 1.020 –1.045: 0.0005 g/ml, T = 20 °C, approx. 350 x 25 mm 6620 standard design 6621-E officially calibrated 6622-ES officially calibrated, with certificate