Source: Tasha's Cauldron of Everything

You have achieved a penetrating precision in combat, granting you the following benefits:

• Increase your Strength or Dexterity by 1, to a maximum of 20.

• Once per turn, when you hit a creature with an attack that deals piercing damage, you can re-roll one of the attack’s damage dice, and you must use the new roll.

• When you score a critical hit that deals piercing damage to a creature, you can roll one additional damage die when determining the extra piercing damage the target takes.