lost my key for 1999 clk 430 what do i do where do i get nta replacemet

Hello, There are a million places online that will sell you a replacement key, but the one that will sell you a replacement key that works is the dealership. You will need your government issues ID, the registration for the vehicle in your name, and the vehicle will need to be present at the time of pickup for the key. Finally, a parts or service employee will need to use the key and record some vehicle information before you take possession of the key.