Professional Battery Hydrometer • Displays a battery's specific gravity on an easy-to-read float; scale ranges from 1.100 to 1.300. • Thermometer indicates what to add or subtract from the float reading to arrive at an accurate specific gravity reading for each battery cell. • Flexible tip offers easy access to the battery cells while the battery is still in the vehicle. Note: Remove foam packing from around the float before using the tool.