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. 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-series lithium-ion batteries, storage batteries, water batteries, and more. Note: They cannot be used with 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 indicators come with a PVC waterproof screen protector and green back-light, enabling clear reading on the LCD display from various angles. Low working current 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 construction 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 convenient use and replacement. The working voltage input range is DC 12V to 84V, with automatic detection for accurate voltage reading based on the connected battery. 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: They cannot be applied for lithium iron phosphate batteries, 1-2 Li batteries in series, and 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.