年份 普通型-左 普通型-右 纤巧型-左 纤巧型-右 1933 Patent Pending 1937 Patent 2032695 1942-1946 Black Crackle, Patent 203695 (This number was stamped in error, it should have been Patent 2032695.)
年份 普通型和纤巧型—左 普通型和纤巧型—右 1986 G to L II 1987 A to L III 1988 A to L IV 1989 A to L V 1990 A to L VI 1991 A to L VII 1992 A to L VIII 1993 A to L IX 1994 A to L X 1995 A to L XI 1996 A to L XII 1997 A to L XIII 1998 A to L XIV 1999 A to L XV 2000 A to L 2000XVI 自2001年起，产品的制造年月以更简单的密码识别。左边仍然以英文字母代表月份，而右边则以阿拉伯数字对应制造年份。 年份 普通型和纤巧型—左 普通型和纤巧型—右 2001 A to L 01 2002 A to L 02 2003 A to L 03 2004 A to L 04 2005 A to L 05 2006 A to L 06 2007 A to L 07 2008 A to L 08 2009 A to L 09 2010 A to L 10
