SR25 Retro Arms SiCr spring with a progressive irregular coil M100

SR25 Retro Arms SiCr Spring with Progressive Irregular Coil M100

Main spring made of steel with a chromium and silicon alloy, for Long type gearboxes.
The progressive coil facilitates the tensioning of the spring without compromising its power.
Spring dimensions:
Internal: 11.3 mm
External: 14.5 mm
Length: 205 mm