Practical designs: The battery capacity voltage indicators feature a switch function button, allowing you to press and check the battery capacity or real-time voltage, then turn off. Equipped with an alarm design, the battery meter display will flash when the battery capacity is below 20 percent. Compatible with various batteries: The battery gauge indicators are compatible with 12V, 24V, 36V, 48V, 60V, 72V, and 84V lead acid batteries, ternary lithium batteries, polymer lithium-ion batteries, 3-series lithium-ion batteries, storage batteries, water batteries, and more. Note: Not suitable for lithium iron phosphate batteries, 1-2 Li batteries in series, or more than 15 Li batteries in series. LCD digital display: The battery capacity gauge features a PVC waterproof screen protector with green backlight, enabling clear reading on the LCD display from multiple angles. Low power consumption, with a maximum of 5 mA. Wide applications: These battery meters with alarms can be used in various settings such as gardens, homes, offices, and more. Durable design ensures long-term service, meeting diverse needs and providing a reliable user experience. Package content: Includes 2 battery meters with alarm, suitable for use and replacement. Working voltage input range: DC 12V to 84V. Automatically detects and displays accurate voltage based on the connected battery. Specifications: Working temperature: 0-40°C Display: Capacity / Voltage Backlight: Green Product dimensions: 2.41 x 1.31 x 0.53 inches / 61.3 x 33.3 x 13.5 mm Mounting hole dimensions: 2.3 x 1.12 inches / 58.5 x 28.5 mm Color: Black Material: ABS Package Contents: 2 x Battery meter Note: Not compatible with lithium iron phosphate batteries, 1-2 Li batteries in series, or over 15 Li batteries in series. The package includes only the items listed above; other products are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowance: +/- 1-3 cm.