I just received an Optimus 200 that I bought from a seller in Sweden. It was sold as complete but disassembled. The vapouriser and inner hood are Radius with the jet marked 102/28. The problem is that the lower vapouriser thread is a smaller diameter than the vapouriser nut thread. Also, the hexagonal part is about 1mm smaller on the LHS one. Fortunately I have spare Optimus 200 upper and lower vapourisers and inner hoods. Below on the left is the vapouriser with the smaller diameter screw thread. On the right is my spare. Can anyone perhaps shed some light on these differences?