1227 Watch Mainspring 2.20 x 0.21 x 521 (20 1/2")(Calibers in description)

Dimensions: 2.20 x 0.21 x 521 (20 1/2")

End Type: T End

Material: Swiss Made Unbreakable

Calibers: 

Longines 10.70, Longines 10.71, Longines 19/57 chrono, Longines 19/57 stem wind, Longines 19/57 key wind, Longines 19/58, Longines 19/70, Longines 19/71A