Cannondale 24 Speed BIke
The cantilevered dropouts date it from 1989 to 1996, the threadless headset to the later end of that. Based on a quick look through the catalogs here, it looks like a 1995 R700, their entry level triathlon/TT bike, which was sold that year with a polished aluminum frame and black fork. That's making the assumption that it wasn't converted to tri-bars later in it's life. It was had a 2x8 (16 speed) drivetrain, not 3x8 (24 speed), but looking at the picture it looks like you may have miscounted the speeds, I see a double not a triple. The brake levers also don't match, but that's an easy switch so they could be aftermarket.