I was unable to locate the serial number (I’ll keep searching), but based on research this bike is likely a 2000 M400 model. This particular one was a rare “SOBE” edition (Cannondale’s racing team at that time was the CAAD2 SOBE Lizard Team). It was a limited edition model that was sold and also given away for promotional purposes. Mine is pretty much stock, except for a shorter handle bar stem, newer black Tektro V brakes and CST light trail tires. A bottle holder and bell have been installed as well.