0700 Watch Mainspring 1.40 x 0.10 x 305 (12") (Calibers in description) Rolex® 1556 Unitas 6431

Unitas 6431

and 70 ply with 60 rows of stitching

Movement has a calendar window at the 3 o'clock position

39 cm long pendulum with dead beat escape and 3 hammers at the side

0700 Watch Mainspring 1.40 x 0.10 x 305 (12") (Calibers in description) Rolex® 1556 Unitas 6431Dimensions: 1. 40 x 0. 10 x 305 (12") End Type: Tongue End Material: Swiss Made unbreakable Calibers: AHO 1166, Alpine 847, Alpina A16, AS 373, Aurore 18, Bulova 4AN, Bulova 10AE, Bulova 10AEC, Bulova 10AH, Bulova 10AHC, Bulova 10AHCD, Bulova 10AM, Bulova 10AN, Bulova 10ANC, Bulova 10AS, Bulova 10AW, Bulova 10AX, Bulova 11ACC, Chezard 86, Chezard 86. 1, Chezard 87, Cyma 456, Cyma 459, Durowe 1032, Durowe 1035, Durowe 1132, Durowe 1135, Enicar 1009,