Greetings from Sweden! This is my first post so: hello Everyone! I've just got (for free almost) Optimus 300 lamp, simillar to the one Nils has here: 1931 Optimus 300 I tried disassembling it before lightning. Unfortunately J-tube broke while trying to unscrew holding nut and mantle holder. I've managed to free these parts (holder and nut) from tube rests but now the tube is shorter by a good 12mm. I'm considering turning a brass extension/adapter to fill this miss but I'd rather replace the J-tube instead. Do you happen to know if any other lamp uses same size tube? I recall someone mentioned that it's a copy of Petromax (?) lamp but which model? Tried finding replacement in Fogas but they don't seem to have it. In the worst case the lamp will serve as a donor for the other 300 but it would feel good to resurect her.