BOOMBOOST 4 In 1 Dual USB Car Charger DC 5V 3.1A Dual Port Car Cigarette Charger with LED Voltage Meter, 12V 24V Fast Charging, Compatible with IOS/Android/all smartphone, iPad, Tablets

The USB outputs seem to work fine, but the voltage, and temperature output display is very hard to read in daylight. Mine has a white case which doesn't help as there is little contrast between the white case and the dull blue display. I wouldn't have bought this item if I'd realised this fact, as I bought it mainly to be used to show the changes in battery voltage in my motorhome.