When I bought my Nova a year ago, I also bought the parts kit. At the time I only gave it a cursory look. A week ago I opened the kit and inventoried it. According to the listing on the box, it was missing a fuel filter and a white O ring. I contacted Katadyn and they quickly mailed to me a replacement kit. The new kit has the two fuel filters as advertised but still does not contain that white O ring. Looking at the exploded diagram of the Nova I only see 5 O rings: 1 at the fuel off/on valve, 1 at the quick connect, 1 where the fuel line meets the spindle, and the 2 on the spindle? Is the white O ring a part for the + or the Polaris? Am I not seeing something?