Fourth Element Arctic Leggings (Men's) - Benthic Scuba
I call this mog "Nazjatar Warrior" : r/Transmogrification
If you still have a bunch of Prismatic Manapearls you can buy benthic pieces to disenchant them and make some extra gold. I bought 588 of them lol, profit. : r/wow
Benthic gear - Wowpedia - Your wiki guide to the World of Warcraft