My watchmaker told me that if I got the Reduced o NOT bring it to him. That piggyback design is a real bear to work on. Most watchmakers simply send back the chronograph module and have a new one sent at a $140 charge (this price was mentioned a couple of years ago, it may have changed)... The dicey nature of the DD module is so well known that it's a "No-Questions asked" replacmeent policy. This is straight from Frank N, RJ's watchmaker and several other independent North American sources. That's the same as the Dynamic Chrono, isn't it? Well, it's the two-register version of the Dubois-Dépraz Chrono Module (2020 instead of 2030). Lemania also made a Piggyback Chronograph modules used on the same basic ETA movement as the reduced... Which leads me to another topic I've been thinking about expounding upon for some time... The visual identification of 3-Register Chronograph movement via Sub-Dial Placement... Here is a short primer... Manual wind, Tri-Compax (Small Seconds at 9, Hour Register at 6, Minute Register at 3): This is the most popular sub-dial layout for classic chronographs, as a result many firms through the years produced movements with this sub-dial arrangement. Among them the Lemania 321 (2320 currently), 187s Series (as seen in the Moonwatch), Lemania ¿1278? (used in 1960's Tissot's and Lemania's, is a hybrid of 321/861 features), the Valjoux 72 series, Valjoux 7736, Venus 178, numberious Universal Geneve's, Excelsior Park's, Zenith HP 146, etc. Bucherer featuring Lemania 873 movement. Rolex Daytona 6263 featuring Valjoux 722 movement (photo courtesy SteveS in NJ) Heuer Autavia featuring Valjoux 7736 movement Gallet Excel-o-Graph featuring Excelsior Park 40/68 Movement Zenith Chronograph featuring Zenith HP 146 movement Breitling Navitimer featuring a Venus 178 movement Universal Geneve featuring a Universal c.283 Thus it's really difficult to determine for certain what movement lies behind a manual wind chronograph with the Tri-Compax layout. Automatic, "Quasi-Tri-Compax" layout (Small seconds at 3, minute register at 9, hour register at 6), can also be manual wind with the substraction of the rotor: Only the ETA 298x/Dubois-Dépraz 2030's and variations have this layout. For the most part if you see a Tri-Compax Layout, but it has a small-seconds at 3 instead of 9 it's an ETA-DD Piggy Back Movement of some stripe... Unless the manufacturer took a Valjoux 7750 and rotated the movement 180 Degrees in it's case to give the pushers a "Micro-Rotor" placement to the subdials like this Ikepod: This Ikepod features a Valjoux 7750 with a 24-hour dial complication rotated 180 degrees in it's case (for the ease of use of the under crystal Slide Rule Bezel... There are a number of companies using this movement, not only Omega, TAG-Heuer among the mid-ranged luxury tier but many smaller firms, a great number of complications seem to be appearing on watches utilizing this movement, one of the more popular is a "Big Date" at 12. But the small seconds at 3 is a give away on nearly all of them. Automatic, Tri-Compax layout (Small Seconds at 9, Hour Register at 6, Minute Register at 3): Zenith El-Primero, Rolex 4130 (new Daytona), Valjoux 7750m (new Tri-Compax layout version). Zenith El-Primero 3019 Rolex Daytona with the new 4130 movement (note the 9 and 3 sub-dial pinions are above the centerline of the watch... This is how you distinguish between the older El-Primero based Daytona's and the new Rolex movement models. I own several of them, Heuer (and later TAG-Heuer) used them extensively in Pilot's model Automatics and some varieties of 2000 series in the 1980's and 1990's... Other manufacturers used them too, including Eterna...   And Doxa recently found a cache of them and came out with a new limited production run featuring this movement: