Is the only difference the size? The HAC is more rectangular. Here are the sizes that gigi posted in the Informative Catalog: Birkin Sizes Birkin 25cm - W25cm x H20cm x D13cm ( short handles only ) Birkin 30cm - W30cm x H22cm x D16cm ( short handles only ) Birkin 35cm - W35cm x H25cm x D18cm ( short handles only ) Birkin 40cm - W40cm x H30cm x D20cm ( short handles only ) Birkin 45cm - W45cm x H30cm x D20cm ( 2 versions, short & long handles ) HAC Sizes HAC 27cm - W27cm x H24cm x D14cm HAC 32cm - W32cm x H27cm x D16cm HAC 45cm - W45cm x H38cm x D25cm Does anyone have an HAC? How do you like it? Are they popular? I think this is an HAC in the picture.