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