Medjay Assassin's Shield

Medjay Assassin's Shield is a shield. When wielded by Noctis, it boosts his strength by +200 for 3 seconds after he blocks an attack.

Source
Medjay Assassin's Shield can only be obtained as a reward from the Assassin's Festival treasure hunt.

Trivia

 * The Medjay, like their historic real-world counterparts, are an Egyptian police force employed by the Pharaonic kingdom in Assassin's Creed: Origins.