The Moore & Wright Spring Dividers are manufactured from polished tool steel and the points are hardened to over 550Hv. The bow spring ensures uniform tension over working range and they are fitted with a centrally mounted adjustment screw. These Spring Dividers comply with BS3123 standards. Note: The nominal size is the distance between the centre of the roller and the working ends of the legs.The Moore & Wright 506 Spring Divider has the following specifications: Size: 150mm (6in).