Similar as Xhorse VVDI BE key pro, users can exchange the VVDI MB FBS3 keylessgo smart key frequency between 315MHz and 433MH.
The reusable FBS3 smart key is compatible with most Mercedes key programmers on the aftermarket.
2 Ways to exchange frequency:
If you have VVDI MB Tool, it is easy to change frequency in vvdi mb software (update software to latest version)
Select Other Function-> Set key remote frequency/ Update MB smart key
You can set frequency between 315MHz and 433MHz
If without VVDI MB, you can change FBS3 keylessgo smart key frequency manually by soldering/desoldering the FRE resistor (marked red in picture below)