Amethyst Ring of Good Fortune

This magic ring has a gold band with amethyst gemstones. The ring has 3 charges, resetting after a long rest.

While attuned to this ring, you gain the following benefits:

Luck (1 charge)
You can reroll an ability check, attack roll or saving throw, possibly changing the outcome of your roll. You can choose to do so after you roll the die, but before the outcome is determined. You choose which of the d20s is used for the attack roll, ability check, or saving throw.

Shield (2 charges)
When you are attacked by a creature, you can use your reaction to cast the Shield spell.  An invisible barrier of magical force appears and protects you. Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack, and you take no damage from Magic Missile.

While you are attuned to this ring, only you can remove it from your finger. If you die, the ring can be removed by another creature.  

Notes: Buff, Jewelry