The Rolex Daytona reference 16520 debuted in 1988 and was the first Daytona to house an automatic movement. Rolex used a heavily-modified Zenith El Primero movement to power the reference 16520. This new Daytona came in a larger case with a sapphire crystal and was available in stainless steel, yellow gold, and, for the first time, two-tone steel and yellow gold. This particular example is a reference 16523 from 1997 and features a beautiful white dial, partially engine-turned gold registers, two-tone steel and yellow gold case, and two-tone bracelet. The reference 16520 line was discontinued in circa 2001 when Rolex introduced their first in-house chronograph movement.