Infernal Amulet
Wondrous Item, rare (requires attunement)
While wearing this amulet, you can use it as a spellcasting focus for your spells, and it grants a +2 bonus to your spell save DC and spell attack bonus.
Curse
You’re unwilling to part with this amulet while attuned to it and you wear it always. While wearing the amulet you have disadvantage on Strength saving throws and Strength checks. Only the Remove Curse spell allows you to remove the item and end attunement.
Corrupting
This item corrupts. See the “Infernal Item Corruption” section.
Source: Chains of Asmodeus p. 268