A little more information.
When input voltage drops below 110 the Sola may boost it by 10% to about 121 volts
If the incoming voltage drops to 105 the Sola still only boosts by 10% to about 115 volts.
Below 100 volts input the Sola switches to 20% boost which ups voltage to about 120 volts.
At 95 volts input boost remains at 20% which results in about 114 for the RV.
On the buck side of 135 volts there is a 10% reduction in voltage to about 121.5 volts.
The other device I was speaking of apparently stays "dead on" 120 volts for the boost. That is why I would choose it over the Sola.
I have used my Sola with 97 volts (measured under load) on shore power at a rural Church.