DIY 3 in 1 Design: This four hole panel includes 2 QC 3.0 USB charging sockets (output: DC 18W max) + 12V socket (output: DC 12V) + ON-OFF -Toggle switches, they are interchangeable. You can also replace each port with additional USB sockets or other suitable means. Two waterproof QC3.0 USB ports: The cigarette lighter socket has two 18W/3A USB ports QC3.0.bis up to 4x faster than conventional chargers. Universal for all 12V-24V cars, buses, RVs, ATVs, trucks, trailers, boats. Marine and more. Voltage display and safe driving: Digital voltmeter display. The real-time LED voltmeter can remind you whether the voltage is at a normal level to ensure safe driving. The blue light is perfect for nighttime use. Note: The voltage display is only visible when this socket is powered and the user has turned on the button. Flexible charging: 1 cigarette lighter is sufficient for multiple portable devices at the same time, such as GPS, dashboard, DVD player , FM transmitters and other small devices