Over the years, Hanna has changed their garment labels a few times, so the design of the label on your item can help you figure out when it was produced. Knowing when your item was released can help you determine the collection name, which can often lead to specific color information as well, information that is key to those looking for matching items!
So here is what your garment label tells you:

a) Your garment was released in 2005 through the present. (Satin tag, size in circle).
b) Your garment was released in 2004 through Summer 2005. (Red, rough, long, skinny tag).
c) Your garment was released in Winter 2002 through 2003. (Satin tag, yellow bars on left).
d) Your garment was released in 2001 through Fall 2002, with some instances through Spring 2003. (Satin tag, logo down left side).
e) Your garment was released in 2000 or earlier. (Rough tag, logo down left side).