2PCS Waterproof LED Digital Voltmeter, DC 12V 24V Battery Tester with Voltage Alarm for Car Boat Motorcycle Truck Caravan

Instant Display: Car voltmeter measures 5–36V DC voltage with an accuracy of ±0.1V. Clear LED display for instant battery status information.
Voltage Alert: DC voltmeter features a smart reminder function. The red LED flashes when the voltage exceeds 14.6V (12V DC vehicles only).
Safe Protection: Round voltage gauge with a 10A fuse, protecting against overload, short circuit, and reverse polarity. In case of reverse polarity, the device will not power on and remains undamaged.
2 Mounting Options: Battery charge indicator installs in a 27mm hole, with or without a panel. The red wire connects to the positive terminal, the black wire to the negative terminal.
Wide Compatibility: This 12V voltmeter is compatible with cars, boats, motorcycles, trucks, RVs, SUVs, ATVs, UTVs, tractors, off-road vehicles, and other 12V and 24V DC systems.