Be aware that just about every camper and trailer dealer as well as every auto part store is now using the same supplier for most camper accessories and parts. Keystone. They are a wholesale distributor only and it is that fun book you look through at the auto parts store. That said Amazon is looking to put all of these type of suppliers like "local" out of business and sells for less than dealer cost direct to you. So if you are looking for someone to bring in this product be aware that you will probably be paying quite a bit more than you see it listed on Amazon since their cost will be more than you see it listed for.
Personally not a big fan of 6v batteries on campers. Lots of people hook them up wrong as well as for the cost of 2-6v you could just have 3-12v group 27's and switch out to LED lights for longer life for less money. Bulk LED light bulb conversions are CHEAP on Amazon as well. If you are using up 3 group 27's you need to learn how to conserve energy and turn off the inverter and TV and Satellite dish... you are camping, or maybe Glam-ping.