The Omega 504 watch movement, also known as the Zenith El Primero caliber 400, was utilized in the Ebel 1911 chronograph watches during the approximate period from 1984 to 1994. It was subsequently replaced by the caliber 137. The caliber 137 features 27 jewels. The Omega 504 movement offers several functions, including an automatic chronograph with measurements of 60 seconds, 30 minutes, and 12 hours, a sub-second display, a quickset date, as well as indications for hours, minutes, and small seconds. The movement was commonly used around 1998.