High grade carbon steel. For marking out and measuring internal and external features. Accurately ground points and quick split nut adjustment. Lengths: spring divider 202mm, internal spring caliper 180mm, external spring caliper 180mm. High grade carbon steel. For marking out and measuring internal and external features. Accurately ground points and quick split nut adjustment. Lengths: spring divider 202mm, internal spring caliper 180mm, external spring caliper 180mm.