SR25 Retro Arms SiCr spring with a progressive irregular coil M100

Description 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