Test your honey with accuracy and peace of mind! The MAGNUM MEDIA 10-30 HONEY REFRACTOMETER (10%-30% Moisture scale) Hand held Refractometer in a cardboard/vinyl, foam-lined hard case. This unit is especially necessary when testing high sugar items like honey. This unit uses ambient light, so no battery or power source is required. Natural, raw honey varies from 14% to 18% moisture content. But that's not the end of it... Honey is hygroscopic; that is, it has excellent water absorbing properties. Thus honey will change in moisture content according to the surrounding atmosphere. This characteristic is important in storing honey because it will absorb water when exposed to high relative humidity (RH) and will give off water when exposed to low RH, until an equilibrium point is reached. High moisture honey will ferment. This is caused by the presence of several yeast species which, as they multiply in the absence of air, produce alcohol. The alcohol may break down to acetic acid (vinegar) and water, giving the honey a distinctly sour or "off" taste and a runny texture with small bubbles, surface heaving or foaming. We love questions! E-mail us if you have any technical questions! Brand new! Ships out ASAP! Professional Grade Honey Moisture Refractometer - 5 Times more accurate than cheap Honey Refractometers! 10-30% Honey Moisture Content Scale, 0.2% Scale Divisions, +/-0.2% Accuracy Comes with a 1.8ml vial of 19.5% Honey Moisture Calibration Fluid - No sickening odors! Comes in a protective foam-lined plastic hard case Automatic Temperature Compensation 10-30'C/50-86'F