Our trademark is a Diamond B; every five years we add a line to it, so you can determine when the item was produced.

First Five years
(1978-1983)
Second Five years
(1983-1988)
Third Five Years
(1988-1993)
Fourth Five Years
(1993-1998)
Fifth Five Years
(1998-2003)
Sixth Five Years
(2003-2008)
Seventh Five Years
(2008-2013)