This is a listing for three dual USB charger that operates off of 12 volts. The material are of high quality and can be used for outside operation. #ycn8/3cu/qplt/4sq USB Chargers: 3.1 amp output at 5 volts. Over-current over-voltage, over-load and over-temperature protection. The intelligent control will prolong the cycle life of the battery. Environmentally friendly, energy-saving, complying with the safe certification standard. High working efficiency: over 85%. Rapid charging without overcharging your battery. specifications: 1: Input : 12V 2: Output : 5V---3.1A 3: Rapid charging for mobile phone 4: IC chip inside prevents overcharging and short circuit The chargers fit in a 1-1/8" holes in panels up to 1-1/2 inch thick with just the backing nut. Panels of unlimited thickness with the mounting plate alone. The connecting cable allows the three chargers to be chained together and a male double female allows the two to be connected to your cable harness.