You need to buy new virgin oem keys which are not available to my understanding and are one time use only.
You can buy Xhorse BE Keys for best quality or any aftermarket BE keys both will work but Xhorse are better quality and logic. If you are using VVDI MB tool Xhorse keys will bring you 200 points from each key which you can use to exchange for token and I tested the frequency can be changed through software or with resistance!
Look at the following table, it includes all Mercedes Benz keys from xhorsevvdi.com to use with VVDI MB tool.
|Item No.||Benz key||Description||Image|
|SA1783||Xhorse BE Key||315mhz and 433mhz; can change frequency; free with 200 points|
|SA1880-C||Xhorse FBS3 BGA KeylessGo Key||315/433mhz; can change frequency free; Free with 200 bonus points; write the data to BE key unlimited times|
|SA1252||New Smart Key 3 button||1. without logo; 2. 433MHZ/315MHZ (1997-2015); 3. The chip can be written for one time only, to write the chip again, need NEC chip.|
|SA1252-B||Smart Key 3 Button 433MHZ for Benz||1.with Two Batteries; 2. covers all non
smart key car types before 2015 3. The chip can be written for one time only, to write the chip again, need NEC chip.
|SA1242-B||Smart Key 3 Button 433MHZ for Benz||1. With Key Shell; 2, with panic button 3. Cover key before 2015 year.|
|SA1243-B||OEM Smart Key for Mercedes-Benz 433MHZ||1. With key shell; 2.cover all non intelligent key car types before 2015|
|SA1253-B||Smart Key 3 Button 315MHZ (1997-2015) for
|1. cover all non
intelligent key car types before 2015; 2. The chip can be written for one time only, to write the chip again, need NEC chip.
|SA1505||3Button Remote Key with Infrared
|1.Best quality PCB Board BENZ Remote Key 433MHZ with IR; 2. for Mercedes Benz 2006-2010|