Surge guard, surge protector...same thing...Having just gone through what you are doing right now...Can be a wide range of prices, depending what you want. Some people are happy with the portable style, where you simply plug into the power pedestal, plug into your trailer power supply and away you go. Others want the more permanent hard wired one, where they can have a display of amps being drawn, any error codes etc. Things to consider...are you confident in your ability to install a hard wired one? Or will you have to pay someone to do it? Is the display important to you? The hard wired one will be out sight, protected from thieves and the outdoor elements. Some of the portable ones don't offer a very high amount of surge protection, and some also won't automatically reset themselves after a power interruption or surge.
You are looking for more than just surge protection...you also want it to detect things like reverse polarity, ground faults, which most do except for the most basic ones.
You do sorta get what you pay for....do some searches in the forum here..there has been a ton of discussion on it of late.
2011 GMC Sierra 2500HD
2014 Rockwood 8289WS, Diamond Pkg.