Sony Ericsson BST-40 Battery. The BST-40 Replacement battery provides a backup power source and also give you the opportunity to increase talk time. Extended batteries offer additional talk and standby time with very little sacrifice in size or weight. Some extended batteries require extended battery doors. Be sure to match your battery with the correct sized battery door cover. OEM designs and manufactures cell phone batteries to match the specific requirements of their cell phones, satisfying the most demanding customer. You can trust the high quality and performance of original cell phone batteries.

Compatible with the Sony Ericsson P1i.