Edit: I have created a website that contains an updated version of the following info called Calibre 1040 (www.calibre1040.com). One of the challenges with collecting cal. 1040 chronographs is that despite the fact that there were seven distinct case shapes (eight if you count cal. 1041) is that dials and hands were compatible across all references. Omega being Omega, they also released multiple dial options for each reference. Some variants were retired before sales to the general public began, some were retired and replaced during production. Others were created by Omega sometime after the entire family was retired and used as service dials. There are 28 distinct dials that could be found by diligent collectors, and two that seem to only live at the Omega museum. Of the 28 only nine remain available (hat tip to @Archer for confirming this via the Omega extranet) from Omega as service dials, so those remaining nine are now seen more commonly than the rest and often on unexpected cases. The following is an attempt to classify these legitimate dials by type for collectors and serve as a resource for many of the questions that we get from time to time along the lines of “how many dials were there for ref. 176.XXX?” This also should help make the seemingly endless variety a little more manageable, at least when it comes to dials. Hands, bezels, pushers crowns, and bracelets are another story. Photos were mostly snagged from the web, cropped and used for educational purposes. Through formatting some of the clarity of the photos was lost. I apologize for that but the photos should be good enough to convey the distinguishing characteristics. Click here to view, save, or download a pdf version of this encyclopedia. Click here for a thread from last year by @cvalue13 which is in my opinion the best and the most comprehensive repository of information and discussion on the cal. 1040 family.