XCSOURCE 12V-24V DC Digital Display Voltmeter Car Motorcycle Red LED Waterproof Volt Meter Black BI181 Universal for: Motorbike Car / Boat / ATV / UTV / Camper / Caravans / Travel Trailer etc. Twist-and-Lock system.Display: 3-bits, LED digital tube, lamp display is red . It works for 12V-24V. Mini size and easy to install,work great for checking Voltage. Mounts in a 1-1/8" hole in panels up, 0.25" thick, a nylon retaining nut holds the meter in place. Measure voltage: 6-30V. Eco-friendly Materials: Acrylic.