1211A Watch Mainspring 2.10 X 0.21 X 470 (18 1/2")(Calibers in description)

Dimensions: 2.10 X 0.21 X 470 (18 1/2")

End Type: Tongue End

Material: Swiss Made Unbreakable

Calibers: 

Balco 548, Cortebert 526, Cortebert 526A, Cortebert 527, Cortebert 533, Cortebert 534, Cortebert 535, Cortebert 540, Cortebert 541, Cortebert 548, Unitas 8, Unitas 231, Unitas 235, Unitas 239, Unitas 243, Unitas 249, Unitas 255, Unitas 259, Unitas 265, Unitas 271, Unitas 277, Unitas 447, Unitas 449, Unitas 471, Unitas 477