Precision blades ensure accurate measurementsBlades from .0015 inch to .035 inch (.038 to .889mm) thickness are approximately 1/2 inch wide by 3-1/2 inch longContains 31 blades with one .010 inch brass bladePrecision blades ensure accurate measurements. Blades from .0015 inch to .035 inch (.038 to .889 mm) thickness are approximately 1/2 inch wide by 3-1/2 inch long. Contains 31 blades with one .010 inch brass blade.