I believe this is try #10 or #11 of rolling eth Threshers/Giant Threshers:
Guess what, they actually
can roll 4 sockets after all... who knew!
Well this seems like a waste of runes for a minor upgrade over her Infinity CV... but hey,
it's her runes and she can do with them as she pleases.

Also with so many twinked chars using Infinity, I thought it doesn't hurt to have another one of these for less switching around in GoMule...
Was mainly hoping for at least 300% ED, and got pretty much no more no less.
Because the CV roll was so bad too (almost worst ED roll), it's almost the same damage and thus actually a nice upgrade for her Merc in the end.