Originally Posted by
Kilroy1988
That's a reference to the brake cable guides on the top tube. They are "double" because they will have cable guide eyelets and stops.
-Gregory
Thanks! (And another of those choices - I love the three top of the TT guides for full length housing a al early '80s bikes. Hate running raw cable along the TT. TiCycles has built me two ti bikes with those three guides. Probably never done it for anyone else. I don't file off the stops on frames I get that have them but they sit there unused.)