Potion of Giant Strength

From Dungeon Master's Guide, page 187. Found on Magic Item Tables B, C, D and E.

Description
Potion, rarity varies

When you drink this potion, your Strength score changes for 1 hour. The type of giant determines the score (see the table below). The potion has no effect on you if your Strength is equal to or greater than that score.

This potion's transparent liquid has floating in it a sliver of fingernail from a giant of the appropriate type. The Potion of Frost Giant Strength and the Potion of Stone Giant Strength have the same effect.