VST Technologies is the manufacturer of cool accessories for your PowerBook. Of the accessories they make, the VST Auto Adapter is definitely one of the most useful. Simply plug it into the cigarette lighter of your car and plug it into the back of your PowerBook (the one tested was a PowerBook G3/292 Wallstreet) and presto, instant power/charging in your car!
If you have a PowerBook, this is definitely one useful item to have.
