ITEM NAME:1.1-1.3 Colored Zone Battery Hydrometer Tester Acid Electrolyte Lead Flooded MME Features: Function: professional for measuring acidity and alkaline storage battery solution. How to assemble: 1. Assemble the red rubber,there is a hole on it, mainly for protecting the densimeter from being sucked into the gasbag. 2. Put the densimeter into the glass tube. 3. Assemble the sucking head. 4. Then assemble the gasbag. Its main function is for measuring electric battery fluid density. When using, put the meter vertical immerse in a transparent container, then you can read electric liquid density from the table at any time. Notice: It is not easy to master the concentration ratio of water in battery, so the densitometer is very important. Usually the density of the electrolyte should be controlled at 1.27. Specifications: Measure Range: 1.10-1.30 Whole Length: 330mm/13" Quantity: 1 Pc Note: Please allow 1-3mm error due to manual measurement..Assemble the sucking head.