I recently purchased on eBay what was described as a TTT adjustable stem for use with Cinelli intermediate-logo Giro bars. Clamp diameter was stated as 26.0, but in the day you could spread a TTT stem bar clamp enough to install 26.4 Cinelli bars at the risk of scratching the bar engraving during installation.
The stem received does not say TTT. I think this is from the 60's when they still went by the name Ambrosia. When I tried to install the bars, even after removing the stem's bar clamp bolt, I couldn't even get the stem past the bend on the Giro bars, don't think there is any way they would take the Cinelli 26.4 raised center section. Were the old Ambrosia bars in the 60's smaller than the ones they sold under the TTT name in the 70's? Could these adjustable stems have been designed for 25.0 or 25.4 (1") bars?