DBx1 needles are the exact same as 206x13 except for the fact that DBx1 needles are round shank. Singer developed the 306 from industrial machines (timing belt) and used an industrial needle. They had to grind a flat shank for it to fit into all the other domestic needle systems. I use a tweezer to orient the needle by the scarfs, have afull rang eof needles to use and not a problem one!