From the manual:
NOTE: Furman’s Classic Series power conditioners do not compensate for high or low AC line voltage. If you frequently move your rack to different locations, derive power from generators, use very long extension cords, travel internationally, or are in an area prone to brownouts, you may benefit from the use of one of Furman’s AC Voltage Regulators.
Although, they do feature surge protection:
Unique to Furman’s SMP is its unparalleled clamping voltage, defined as the amount of voltage that is allowed to pass through to your equipment when the protection device is subjected to a transient surge or spike. While other designs offer clamping voltages that are well above 600 Vpk, Furman’s SMP clamps at 376 Vpk, (266 VAC RMS) even when tested with multiple 6000 Vpk - 3000 amp surges!
