Part Numbering - Delta AFB0612SH-ABF00

What does the suffix A, B or F00 call out in this Delta Products Group part AFB0612SH-ABF00?

A ==> newer revision
B ==> rib frame
F00 ==> tach output ( 3 wires ) Take a look at the part number breakdown, and how the “B” in the suffix can be left blank.

http://www.delta.com.tw/product/cp/dcfans/download/pdf/general_info.pdf#page=6