Stygian Vise is a belt Abyss base type. The belt has the unique “Has 1 Abyssal Socket” implicit modifier, which allows an Abyss Jewel to be socketed into the belt.
Abyss Changes 3.21
Abyssal Depths now always contain an Abyssal Lich. Abysses have a chance to spawn a Stygian Spire in place of their reward chest, which drops a Stygian Vise, jewels and other items. You’re now guaranteed to always get a four-hole Abyss alongside your Abyssal Depths, rather than just a single hole. Also updated Abyss passives on the Atlas Tree, Abyssal Lich encounter balance, Abyss uniques and Abyss Scarabs.
It is now possible for a Stygian Spire to spawn in the place of an Abyssal Trove at the end of an Abyss, which will drop all of the jewels and other items you would normally receive as well as a Stygian Vise.