Lenmar Battery for HP, iPAQ 3800, and 3900 Series 3.7V 1700 mAh Fits HP Ipaq 3800 & 3900 Series May Require Skilled Installer Or Special Tools Fits HP iPAQ 3800, 3900 Series 3.7V 1700mAh Lithium Polymer 2 Year Warranty Warning: This Battery may require Skilled Installer or Special Tools to Replace. For Skilled End Users Only.