A favorite gadget

How many times do you go to a workshop, need a power source and are no where near one?   I found this at Radio Shack and love it.  It's a power inverter with ports for many devices.  I use it mainly with my Artograph lightpad.  Since the lightpad only uses a few amps and the unit is for 90 watts, I've been able to leave it on all day without running out of power.   It is a bit heavy but small so it fits in my calligraphy suitcase.  It cost around $60 on sale and definitely worth it.
Here's what it looks like: