rotring 300 Series Sanford rotring Holding GmbH, Germany lead diameter(s) mechanism composition variations production date origin 0.3, 0.5, 0.7, 0.9 mm (and 2.0 mm, see below) pushbutton incremental advance clutch plastic barrel, grip, and indicator; metal mechanism and clip none 1990s Germany special features lead degree indicator rotring 300 / 2.0 Sanford rotring Holding GmbH, Germany lead dia..