The calibration knob can be tightened with a simple turn
Atago MASTER-S28alpha specs:
Fruit Juices
1ml Measurement time Instantaneous Body type Copper alloy with a nickel-chrome coating Illumination Ambient light
To calibrate: Place one drop of distilled water on the prism face and turn the manual calibration screw to it reads 0 Brix if necessary
Atago MASTER-2T Hand Held 28-62% Brix, ATC Antifreeze Refractometer The calibration knob can beItem Description: Atago MASTER 2T Hand Held 28 62% Brix Refractometer with Automatic Temperature Compensation (ATC) A FAVORITE OF FOOD INDUSTRY PROFESSIONALS! Ideal for Jams, Jellies, Fruit Juice Concentrates, Soda Concentrates (NOT for Soda Fountains see our other, lower Brix Refractometers for that application), Ketchups, Barbeque Sauces, Glazes, Fudges, Chocolate Sauces, Salad Dressings, and more. We know a thing or two about how and where to use