Yes Bob the guys are correct. To be 12V it must be a DC unit for battery use, or you will need either and Inverter or converter !
Also European frequency is 50Hz, though this is not an issue as any 50Hz motor will run at 60Hz no problem. The Euro voltage is 220/230/240V or 380/400V.
I expect this is the main reason why the manufacturer will not sell it here. There may also be a Certificate of Conformity required, "UL" in your case whilst the Euro one may be "CE" marked. They are both pretty similar but unless the investment has been made to ensure complianceb the products will not inter trade !
Regards,
Ben in Ireland.
'64 230SL 4sp.