All of the Compaq Presario 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 compaq batteries can be passed easily through the test of short-circuit, over voltage, low voltage etc. And our compaq battery has been tested on related compaq laptop to ensure that them are 100ompatible original product. In addition, we also provide 30 Days Money Back and One Year warranty to ensure your confidence with our compaq laptop batteries. We look forward to cooperating with you!