info on surge protectors

I work as a support engineer for a major Surge Protector / UPS company that focuses on computer protection. We make everything from little desktop UPS units & powerstrips to whole data centers solutions. Unfortunately we don't make any stand alone 30 amp surge products. Looking at my options for RV type products I am seeing an awful lot of snake oil solutions and very little that I have confidence in. None of the products I have seen so far are UL listed and none of them appear to publish their let through voltage. You can very cheaply engineer a product to have a very high Joule rating, but it doesn't mean that its necessarily a good surge protector. Let through voltage is the only number that really means anything, and it is what UL uses to determine adequate surge protection. It determines the maximum amount of voltage that could be let through during a large surge. The usual test is a 6000v surge and you would want a maximum of 330v to be able to make it through. Better surge protectors would allow less, but 330v is considered adequate for most applications.