Measures from 0 to 32 Brix and 1.000 to 1.120 on the usual scale we use which is specific gravity
Brix is a scale used by fruit juice producers, we tend to use specific gravity which th ethe scale on most hydrometers.
NIce and simple to use, comes with instructions and calibrating screw.
You need to calibrate it with distilled water, we just scraped a bit of clean ice off the freezer and used that on ours. It seems to work ok!