All of the Dynabook laptop batteries have the protection function of over charge and over discharge, over heat, over current etc. We have passed the CE authentication of Europe, and it produces according with the UL standard, all of Dynabook batteries can be passed easily through the test of short-circuit, over voltage, low voltage etc. And our Dynabook battery has been tested on related Dynabook laptop to ensure that them are 100% compatible original product. In addition, we also provide 30 Days Money Back and One Year warranty to ensure your confidence with our Dynabook laptop batteries. We look forward to cooperating with you!