BATTERY CAPACITY VOLTAGE METER - The battery gauge give you a bar and number of volts or power left on battery in use, so as to determine when it must be recharged. Besides, it flash to alarm the battery capacity is lower then 20%. SUITABLE FOR VARIOUS BATTERY TYPES - Works with ternary lithium battery, polymer lithium-ion battery, 3- lithium ion battery, storage battery, water battery, etc. (Note: Not fit for lithium iron phosphate batteries, 1-2 li batteries in series and over 15 li batteries in series.) SLEEPING MODE & BLUE BACKLIGHT - Our battery monitor can be set auto off after 10 seconds or always display either % or . Blue LCD display is easy to read, red as it is impossible to read under the sun. Built-in reverse protection. WIDELY USE - These battery capacity voltage meters are small and compact with rear covered. Simple wiring, you just need to connect the red wire to positive and black one to negative. ly fit for golf cart, boat, carm, RV, motorcycle,. DETAILED INSTRUCTION - Comes with 1 battery meter, 1 2-pin wire. No need to worry about how to set the battery meter, the instructio steps. Voltage Display Range: 9-100V Working Current: less than 5mA Sleeping Mode Current: 12uA (12V test) Working temperature: -10℃~50℃ Applicable Battery: Acid Battery (DC 12/24/36/48/60/72/84V); Lithium battery (3 ~ 24 strings); Lithium iron phosphate battery (4 ~ 26 strings) colour: black Material: ABS Package Contents: 4 x battery capacity voltmeter (blue backlight) 4 x 2 needle thread (black thread and red thread) NOTE 1.Since the setting button is on the back of the meter, the meter must be set before installation. 2.The operating environment is -10°C~50°C, more than 50°C shorten the life of the LCD. Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.