Relative density, or specific gravity,is the ratio of the density (mass of a unit volume) of a substance to the density of given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest (at 4 °C or 39.2 °F); for gases, air at room temperature (20 °C or 68 °F) is the reference. The term "relative density" is often preferred in scientific usage.

If a substance's relative density is less than one then it is less dense than the reference; if greater than 1 then it is denser than the reference. If the relative density is exactly 1 then the densities are equal; that is, equal volumes of the two substances have the same mass. If the reference material is water, then a substance with a relative density (or specific gravity) less than 1 will float in water. For example, an ice cube, with a relative density of about 0.91, will float. A substance with a relative density greater than 1 will sink.

Temperature and pressure must be specified for both the sample and the reference. Pressure is nearly always 1 atm (101.325 kPa). Where it is not, it is more usual to specify the density directly. Temperatures for both sample and reference vary from industry to industry. In British brewing practice, the specific gravity, as specified above, is multiplied by 1000.[3] Specific gravity is commonly used in industry as a simple means of obtaining information about the concentration of solutions of various materials such as brines, sugar solutions (syrups, juices, kinds of honey, brewers wort, must, etc.), and acids.

In addition to the Bluetooth-enabled refractometers, ATAGO ® released refractometers with near-field communication (NFC) technology for the ease of storing and sharing data with phones, tablets, laptops, and other NFC-equipped devices. Simply by tapping NFC-equipped devices, up to 100 measurement data with the date and time are transferred in a matter of seconds. The NFC solution is simpler and prevents typical human errors in data collection and data generation.

With the ever-evolving movement of profound change in how humans interact with machine automation, this upgrade seizes one’s time to write down measurements with a pen or paper.

The Palette series - digital refractometers, are compact battery-operated instruments that can display the measured values of samples quickly with one touch of the START switch.

	Compact and easy to carry		Calibration with water
	Battery operated		Digital display
	Automatic Temperature Compensation (ATC)		External Light Interference

Equipped with a new technology "External-Light-Interference" (ELI)* that enables you to take accurate measurements with ease and confidence near at a window or outside. * Patented