PARKER # 42 1/2 eyedropper, black chased hard rubber with decorative gold bands ( c. 1898 - 1910 ), PARKER # 21 , eyedropper , black hard rubber with decorative gold bands ( c. 1898 - 1910 ) , PARKER # 18 , jointless, eyedropper, black hard rubber . Note the end - barrel groves introduced by patent on improved anti break- cap ( c. 1900 - 1918 ).