People would end up purchasing new tools, rather than ordering older batteries from the factory. It was odd, even though each generation was a same voltage, NiCd battery, there would be a slight change to a a bump or ridge on its case, preventing interchange between versions. It was common that I'd bear the brunt of a shopper's frustration when they learned that each year's version of the store-brand tools had an battery configuration incompatible with the prior model. Years ago, I worked a second job, at a department store selling their popular exclusive brand of tools. They've outlasted and out performed any other brand of cordless tools I've owned by several years, leaving me a bit of a fan-boy. I've had my own set for about 8 years, and all the tools are still going strong. They're certainly the most common brand on the construction sites I've visited. It's been one of the most popular lines of professional-quality cordless tools, for a very long time. I believe DeWalt's 18 volt line of cordless tools has been in the market for about 20 years. I've run it through its paces for a month on a variety of my tools. When DeWalt gave me an early-bird chance to try out their new battery adapter and bring modern battery technology to my older tools, I couldn't wait to put it in action. Regular readers of this blog know that I've been personally wielding DeWalt 18 volt cordless tools on my projects for years.

Dewalt 18v 20v battery adapter