VVDI MB Tool Benz key programmer, if you have uesd/2nd-hand EIS with working key,you can do like this for W221 all key lost:
1.read all key lost EIS data-> save EIS data
2.read used EIS data enter password,get erase password->renew used EIS.
3.load step1 EIS data to renewed EIS with password->write EIS data
4.load EIS data(with key password)->prepare key file
5.input new key to device IR reader->load key file->write
6.insert new key to EIS->EIS will learn the new key->key learn success