Ref. 3971E, Screw-Down Sapphire Back
Perpetual Calendar 3971 — Ref. 3971E, Screw-Down Sapphire Back
1987–1990
Screw-down sapphire back; hallmarks on the outer lug sides, a practice dropped mid-production. Example: pink gold, 1989, one of eight pink-gold 3971s known.
About 170 made.
No verified image of this watch yet
Identifying details
- Perpetual calendar
Calendar that accounts for month lengths and leap years.
- Moon phase
Variants of 3971
Reference overview →| Variant | Production |
|---|---|
| Snap-On Sapphire Back | Undated |
| Ref. 3971E, Screw-Down Sapphire BackCurrent | 1987–1990 |
Case & movement
- Reference
- 3971
- Production
- 1987–1990
- Case serials
- Case diameter
- 36 mm
- Movement
- Manual winding
- Date
- Yes
- Caliber
- Patek Philippe CH 27-70 Q
Dial, bezel & hands
Unknown attributes are left out rather than guessed.
Movement
Patek Philippe CH 27-70 Q
Heavily modified Lemania 2310 column-wheel chronograph with perpetual calendar, moon phase, leap-year and 24-hour indications. Replaced the Valjoux-based in the ref. 3970 and also powered the ref. 5020.