The Black and Decker Electromate 400 is one of the must have devices in your home / car / garage in the event of power failures and for roadside emergency car repairs.This all-in-one device is much less expensive than the sum of its parts bought individually and far more attractive and portable.Before you start using this device please read the instructions provided, the instructions say to fully charge the battery for 40 hours or more to make sure it fills to maximum capacity. Lead acid batteries don't like to be fully discharged.Inverter function:The "400" in the name indicates that the inverter is cable of peak bursts of 400W power draw, but in practice you should probably only be using this to power devices in the sub 50 watt range Please do not Plug-in an air conditioner or a toaster and expect it to work. This is not designed to run such high power drain appliances.AC inverters such as these are not 100% efficient so if you are running appliances off the inverter built into this unit; expect a useable capacity more like 150 watts when the battery is fully charged.My personal experience is that you can run a fully charged Electromate 400 inverter with 4 CFL Bulbs (13W each) for about 2 hrs and 45 mins before the inverter shuts off. At this stage, the battery voltage is well below the 11.2vDC to about 10VDC when the inverter just quits working to prevent battery damage.*** TIP ***Use the accessory plugs for 12v more often than the inverter, you draw power directly from the battery which is smarter way to use the device than using the inverter.For example, if you wish to charge your cell phone first attempt to use the car accessories supplied with your cell phone if available rather than using the Electromate 400's inverter and using 120V power adapter.Jump Starting and Air Compressor function:The car starting and air compressor functionality come in handy surprisingly more often than you think especially if you own an older car. These simple functions found in Electromate 400 can be lifesavers.It has plenty of power to jumpstart a 4cyl or may be certain 6cyl cars but do not expect to start a v8 or bigger car using this. The Cold Cranking amps needed to jumpstart bigger car is just too much to ask from a 19Ah sealed lead acid battery which is rated to be at 228 watts at best .The Air compressor is only good for keeping your tires to PSI levels recommended by your car manufacturer; do not expect to use this to completely inflate a 100% flat tire. The compressor is noisy and will shutdown to save itself from getting overheated. It can however be used to inflate bicycle tires and inflate mattress without much issues.Area light function:It is a neat idea but  falls short of my expectations, Especially when you have been using Electromate 400`s inverter function for about 2 hrs or more and battery voltage drops to about 11.0v the Area light fails to glow! while the inverter still keeps working!I fail to understand why limit the area light's LED power draw? This is the least power consuming part of the unit and I was expecting this would stay illuminated till the battery completely dies (Perfect use in emergency situation)It was strange to see that Inverter's fan keeps spinning under low battery condition but area light stops working - Go figure!PROS:[+]  Very well built, compact and can take good amount of abuse[+]  All-in-one device is much less expensive than the sum of its parts bought individually.CONS:[-]  Area light LEDs stops working even if battery has enough juice to run the inverter and cooling fanStill well worth the money as this all-in-one device is much less expensive than the sum of its parts bought individually and far more attractive and portable.