I happened on a pair of probable amplifiers, I was wondering if anyone could
tell me more about them?

VICOR Company---Manufacturer
FlatPAC---???Type of Amp???
600 Watt
AC-DC Switchers
MOdel No: VI-NUL-IM
Voltage: 100-120/200-240V
Current: 13.5/6.8 A
Frequency: 47-440HZ
Output 1: 28V 21.5 Amperes / 600 Watts

Several US Patents