Effective Immediately, the Fathom 600 is now called...

[phyrexia]

The "M6 Carbine". There was some sort of trademark issue and Mesa had to change the name. The only difference to the amp is going to be cosmetic. There'll be a mesa engineering logo there instead of the silkscreen.

 

[THE_L1ZARD_KING]

I heard it was JL audio that has a copyright on the name Fathom so Mesa decided to change the name rather than pay out the nose.

http://home.jlaudio.com/products_subs_pages.php?page_id=4