Answer
Most watches sold as a fake Speedmaster with Calibre 9900 do not hold Calibre 9900. They hold a clone built on a Valjoux 7750 layout, or a 7750 with decorative plates and a changed rotor. The real Calibre 9900 is an Omega in-house automatic chronograph with a co-axial escapement, a column wheel, a vertical clutch, and METAS Master Chronometer certification. A case maker can copy the dial print. It cannot copy the movement serial, the test card data, or the service record at an Omega center.
What Calibre 9900 is
Omega lists Calibre 9900 as a Master Chronometer automatic chronograph. Specs: 28,800 vph (4 Hz), 60-hour power reserve, co-axial escapement, silicon balance spring, magnetic resistance to 15,000 gauss, and precision of 0/+5 seconds per day across eight METAS tests. The 9900 powers the Speedmaster 44.25 mm with two counters: 60 minutes at 3 o'clock, 12 hours at 6 o'clock. The date sits at 9 o'clock.
What runs inside a fake "9900"
An Asian 7750: cam switching, 25 jewels, 28,800 vph, about 40 to 48 hours of reserve. The chronograph snaps through a cam, not a column wheel. Rotor text reads "9900 Co-Axial Master Chronometer." The text is engraved shallow. Letter spacing is wrong. Movement serial numbers are stamped on a bridge. Omega can check that number.
Checks that need no tools
- Date position. 9900 Speedmaster puts the date at 9 o'clock. Many fakes place it at 3 or 4:30, or leave it out.
- Counter layout. 60-minute totalizer at 3, 12-hour totalizer at 6. A 7750 base has a 30-minute counter and a running seconds hand at 9.
- Minute counter at start. A vertical clutch moves the minute counter in a smooth sweep. A cam jumps it one minute the moment you press start.
- Pusher feel. A column wheel gives a light, short click. Cam switching feels heavy and travels further.
- Balance spring. Silicon reads dark blue or purple through the sapphire back. Steel springs read bright.
Papers and serials
Master Chronometer watches ship with a METAS card that lists the test result for one movement serial. That serial matches the case. Fakes ship with a copied card and a serial that does not match, or one Omega's service system does not return.
What photos cannot prove
Photos do not show escapement type, balance spring material, or true power reserve. Two tests settle it. First, run the watch 48 hours off the wrist and check if it still runs. A 7750 stops near 40 hours. Second, put it on a timing machine in five positions for 24 hours. Real 9900 output stays inside 0/+5 seconds per day. Some sellers photograph one movement and ship another.
Check four numbers before payment: movement serial against case serial, METAS card data, date position, and power reserve after 48 hours.