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. Fit for different battery: 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-cell lithium-ion batteries, storage batteries, water batteries, and more. Note: Not suitable for lithium iron phosphate batteries, 1-2 Li batteries in series, or over 15 Li batteries in series. LCD digital display: The battery capacity gauge indicators come with a PVC waterproof screen protector and a bright green back-light, enabling clear reading on the LCD display from various angles. Low working 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 practical battery monitoring experience. Package content: You will receive 2 pieces of battery meters with alarm, suitable for use and replacement. Working voltage input ranges from DC 12V to 84V, with automatic detection to accurately match the battery voltage. Specifications: Working temperature: 0-40°C Display: Capacity / Voltage Back-light: 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 suitable for lithium iron phosphate batteries, 1-2 Li batteries in series, or over 15 Li batteries in series. Only the above package content is included; other products are not included. Note: Lighting and different displays may cause slight color variations between the item in the picture and the actual product. Measurement error allowance is +/- 1-3 cm.