When we were at the NEC show I spoke to somebody on the Thetford stand & asked if they had something similar to the SOG. He showed me on the newer C250 there is provision under the toilet for an Automatic Ventilator. Which is just a fan & carbon type filter isn't that a SOG? It was all the SOG that I fitted to my last van was. From what I remember it was around £40 & the benefit was it vented the toilet under the van so it didn't needed anything fitted to the door. Has anybody fitted on of these & does it work ok or does anybody know where you can buy one, up to now I haven't seen it listed anywhere. Maybe they don't push it too much as they would lose revenue from the chemicals they sell.