System-S Backup Battery Charger Extender For Palm Palmone Zire 72 v Tungsten E Zire 31 72 Insert four conventional 1,5V Mignon AA size batteries into the pack and have a portable power source Total Total running running time with connected battery adapter will be extended for hours (depending on the used batteries up to 8 hours) runnconnecg with a ac adapter or charging cradle Charges your battery or provide backup power Lightweight , slim and compact size