From the website:
"Simple and effective, the Value Charger can charge four AA or AAA rechargeable batteries at a time. A foldable wall plug makes for easy portability and handy storage. And the Value Charger can charge other brands’ rechargeable AA or AAA NiMH batteries as well. It includes StayCharged Rechargeables with Duralock Power Preserve™ Technology, now guaranteed for three years in storage."
