Twain used a Smith & Todd gold-nibbed pen dated 1868 (I own Twain's Smith & Todd pen). In the 1880s he used a Paul Wirt dropper pen and wrote admiringly of its smooth writing qualities which they used in their advertising. He later used a Conklin fountain pen whose filling lever projected slightly from the body of the pen and kept it from rolling off a desk, and they used his endorsement in their ads as well. I have advertising from at least one other pen-maker who claimed Twain used their pens, but their name escapes me at the moment. Conklin, still in business, has made new "Mark Twain" pens to celebrate their connection with Twain, although I don't know if the model they have reproduced is solidly documented as the very model Twain actually used. Kevin Mac Donnell Austin TX