I was pleased with this inverter for car use. It worked both while driving on the road, and while car camping with the engine running.
The DieHard inverter arrived in the hard plastic shell material that you need a knife to open. Once you get the inverter out, all you have to do is plug it into the car cigarette lighter, and then plug the other end into whatever device you want to charge.
The little fan inside the inverter is audible as white noise. Not very loud, but noticeable. A little green light shows when the device is plugged in and ready to use.
I found the DieHard inverter very easy to use - just plug and play. I used it to charge my iPhone, my Kindle and my Toshiba netbook. You can use your device AND charge at the same time, which is a nice feature.
I appreciated the choice of two size charge outlets. You can plug in the USB of your choice, or a regular three-pronged plug for small appliances. 140 watts is plenty of power for the small electronics I want to use while traveling or car camping.
The inverter is small enough to unplug and put in your glove box or console drawer, so you don't have to leave this item in view when you leave the car.
The inverter fits a little tightly in my lighter socket and you have to really push it in well (I drive a 97 Jeep Cherokee Laredo). Even so, while driving on washboard or dirt roads, the inverter fell out of the socket (very suddenly) a few times. I don't think this device was created with off-roading in mind, but this is something to be aware of.
Since the inverter only supplies 140 watts, you need to be careful what kinds of appliances you put in for charging. I don't think this is enough wattage for large-draw devices like vacuum cleaners, coffee pots, blenders or microwave ovens. I'd stick to electronics unless you know for sure what kind of watt-draw capabilities something has.
With a decent price point, the DieHard 140 Watt Power Inverter covers many basic needs and is a very good device for travelers on a budget. If I ever had to live without electricity in my house (whether through a catastrophe or for budgetary concerns), this inverter would supply a wonderful and constant backup charge for all my electronics. I could even save money in my daily life by getting a free charge for my phone and such every time I took a drive, instead of using an outlet at home.
Available from Amazon or Ace Hardware: DieHard 140-Watt Power Inverter with Built-in USB Port