Why don you offer nickel metal hydride (NiMH) or nickel cadium (NiCd) batteries?
The StenLight is perfectly capable of running from 7.2V or higher NiMH or NiCd battery packs. However, Lithium Ion provides more energy per unit volume and significantly higher energy per unit weight than either of these technologies. Lithium Ion also keeps its charge much longer. Finally, Lithium Ion is much easier to charge reliably regardless of its previous charge/discharge history. As the chargers for Lithium Ion and NiMH/NiCd are totally different, we have standardized on Lithium Ion for all of the batteries we offer.