Omega 816, 1861 Speedmaster Mainspring

Genuine Generale Ressorts Swiss-made replacement mainspring for the Omega 861, 1861 and related manual-wind Speedmaster movements.

The 861 and later 1861 families powered generations of Omega Speedmaster Professional watches and are among Omega’s most important manual-wind chronograph movements. These are highly collectible watches that continue to be regularly serviced and restored.

For a movement like the Omega 861 or 1861, mainspring quality and dimensional consistency matter. There’s no mystery about what you’re installing: GR33001 is a branded Swiss mainspring made by Generale Ressorts, a leading specialist manufacturer of watch mainsprings.

Is GR33001 compatible with the Omega 861 and 1861?

Yes. GR33001 is a replacement mainspring for a broad family of Omega manual-wind chronograph movements spanning the 861 and 1861 generations.

Compatible Omega Movements

860
861
863
865
866
920
930
1861
1861A
1863
1866

Specifications

Manufacturer: Generale Ressorts
Manufacturer Part Number: GR33001
Type: Manual-wind mainspring
Height: 1.30 mm
Thickness: 0.115 mm
Length: 420 mm
Barrel Diameter: 10.5 mm

Amplitude Watch Parts ships from the USA, so there’s no need to worry about long overseas shipping delays or tariffs.