The 8a� leg length is the ideal size for craftsmen and carpenters looking for a general purpose divider. Itas not too big or not too small to take most measurements scribing drawing or simply anything that comes your way. The spring divider features a sliding speed nut that enables fast measurement adjustments. To lock a measurement in place have the speed nut make contact with the centering collar. Then youare set to do repeat measurements without repeatedly using a ruler/measuring tape!