I went to the ProtectAll site (referenced by dternst above) and clicked on their dealer locator. Sure 'nuf, even in my dinky little one-horse town, I went down to the local store that rents campers/RVs, and they had it in stock. The price was low enough that -- even with paying sales tax -- it was a better deal for me than online ordering. And they told me that, when I get low, they'll order it if/when I ask for it. Pretty good service, and it supports our dinky local economy.