No, and we probably shouldn't try it
And here is why!
Leitner headsets sold in the US are set to the correct frequency for your territory which is 1920 - 1930 MHz. In Europe the DECT frequency is different 1880 - 1900 MHz so this frequency would be required to meet the regulations. As the EU approval for our wireless headsets is based on units with the correct frequency, using a US version would also not be covered by the approval.
Furthermore, these headsets are designed to work with the outlets that run at 110v, and many European outlets run at a much higher voltage, often around 220v. This amount of power could fry the Leitner, so you should probably purchase locally.