From the product description, check product page for current description, price and availability:

Hydrometers are one of the most necessary tools in homebrewing. Our Triple Scale Hydrometer allows you to read your gravity, potential alcohol content, and brix.

A hydrometer is perhaps the most essential piece of measuring & testing equipment in any home brewery. Used it at every stage of brew to keep up with the health and progress of your brew.

This convenient hydrometer features three scales–specific gravity, potential alcohol and brix–and is handy for both brewing and winemaking. It measures 9 inches long and comes with complete, detailed instructions for proper use.

Scale Ranges:

Specific Gravity: 0.982 – 1.160
Potential Alcohol: 0-20%
Brix: -4 – 35