Girth of Torment is potion belt slot item.
See
this for all potion belt slot items.
From my other response:
Certain items are tagged for extra potion belt slot flag. If you look at the raw data on Lucy
Girth of Torment, you'll see a potionbeltslots entry, but Lucy doesn't correctly parse this data. However, 13th floor's raw data does correctly parse this information:
Girth of Torment.
There is no information on the item display window to give an indication of this feature, it's only known either equipping the item, and noticing the change, or via the raw item data.
Yther Ore.
Edited, Jan 4th 2010 4:38pm by Yther