Battery hydrometers are designed to detect the state of charge of a battery by measuring the electrolyte from each cell. The hydrometer contains an indicator that shows the density of the electrolyte: the denser the electrolyte, the higher the state of charge of the battery.

Thick-walled plastic housing resists breakage Direct scale provides extra large markings Test battery life instantly and accurately, whether the battery is hot or cold Works on all 6-12-24 volt systems