What does AA mean on a lens item code?
I'm looking for a used version of this lens:http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_70_300mm_f_4_5_6_is_usm#Overview and I'm finding many with the item code listed as 0345B002, 0345B005AAI've seen a photo of the box ...