I believe it's a 380mm (blade length) stretched version of the 450L. The '470' name is confusing as most other manufacturers now go by blade length, but i guess Align wanted a size designation that fits between the existing 450L and the 500L.
Also interesting that they have gone away from the DFC head on this one too, seems like they are phasing it out on all their new models. The new 700 has also dropped the DFC design.