Rime Rimmed Mariner's Rebreather
The Rime-Rimmed Mariner’s Rebreathers use the standard aquabreather skin (which you probably already have unlocked from your starter gear). It doesn’t have a unique skin.
The icy effect around your character is unique to the ITEM itself. You can wear the Rime Rebreather and apply the Benthic or Consortium mask skins on top of it, and your character will still have the icy effect underwater.