Audio aero Capitole MKII Cd player

Dear Sirs,

Hi! i have an Audio aero Capitole MKII Cd player and in my country the voltage is 230V . And i  sold the unit to U.S.A so the buyer asks if the voltage is capable for 120V . In the rear plate of the unit where the Power cord Fuse location writes 100/120/220/230/240 VAC 50/60Hz , is this means that are automatic voltage selector ? or we have to make something internal in the unit to change the Voltage to be capable to use it in USA? And if not of any aobove should it be ok if we install outside stepdown transformer from 230V-120V?

Best Regrds
Marios Charidemou