These handheld refractometers have a built-in automatic temperature compensation system from 10 to 30°C. Unit measures only 8L x 1 1⁄4W x 1 1⁄4H". Brix scale is 0.0 to 32.0% with an accuracy of ±0.2%.

Master-alpha refractometer 4938A has an IP65 rating for water resistance (excluding the eyepiece).