Good shape, tried once. Missing literature, rough box.
The Furman AR-20 Series II delivers a stable stream of AC power to protect equipment from problems caused by AC line voltage irregularities such as sags, brownouts, or over-voltages - all of which can cause sensitive electronic equipment to malfunction or sustain damage. Featuring a generous 20-amp capacity, the AR-20 Series II accepts any input voltage from 97V to 141V and transforms it to a constant 120V. Voltages beyond this range are also converted to usable levels, unless they are extremely far out of range, in which case the unit will automatically power down to prevent equipment damage.

Furman AR-20 Series II Voltage Regulator at a Glance:

• Regulates, filters, and purifies AC power
  
• Delivers stable voltage with precision
  
• Regulated, spike-suppressed outlets
  
• Employs Furman's Series Multi-stage Protection Plus
  
• Linear Filtering Technology for noise-free AC
  
• SMP clamps over-voltages without sacrificing itself
  
• Extreme Voltage Shutdown powers down connected gear safely

Click here for more details