Shimano dating code, normally 2 letters, the first is the year, the second is the Month, if only one then it be the year. This is QD = 1992 April. A 1976, B 1977, C 1978, D 1979, E 1980, F 1981, G 1982, H 1983, I 1984, J 1985, K 1986, L 1987, M 1988, N 1989, O 1990, P 1991, Q 1992, R 1993, S 1994, T 1995,U 1996,V 1997,W 1998, X 1999, Y 2000, Z 2001, A 2002, B 2003, C 2004, D 2005, E 2006, F 2007, G 2008, H 2009, I 2010, J 2011.