1. Digital Handheld Refractometers: These are handheld devices that measure the refractive index of a liquid sample. They are typically used in the laboratory or in the field for quick and accurate measurements.

2. Digital Polarimeter: This type of refractometer measures the polarization of light passing through a sample. It is used to measure the optical rotation of a sample, which can be used to identify the type of sugar present in a sample.

3. Digital Abbe Refractometer: This type of refractometer measures the refractive index of a sample using a prism. It is used to measure the refractive index of a variety of materials, including glass, plastic, and metals.

4. Digital Refractometer for Beer: This type of refractometer is used to measure the sugar content of beer. It is used to measure the specific gravity of beer, which is used to determine the alcohol content.

5. Digital Refractometer for Wine: This type of refractometer is used to measure the sugar content of wine. It is used to measure the specific gravity of wine, which is used to determine the alcohol content.