1. Battery tester 2. Avoids dead battery and helps extend battery life 3. Tests battery life hot or cold 4. Material: PVC 1. Hydrometer Battery tester2. Applicable to 6, 12, 24 V systems3. Detects overcharge4. Battery tester can fast and accurate testing of battery conditionInstruction:1. Remove battery caps.2. Insert nozzle of hydrometer in battery ceil, squeeze bulb until fluid reaches level ...