This is a full sleeve, from the pauldron to the gauntlet, armguard reinforced with adamantine, one of the hardest substances in existence.
The armored sleeve consists of segmented and shaped, overlapping metal bands that cover the entire arm.
Straps from the pauldron reach across the chest and under the opposite arm with utility straps securing the harness connections over the shoulder and clavicle area.

While wearing the manica, you gain a +1 bonus to AC if you are wearing no armor and using no shield.
If critically hit during combat, the wearer may use their reaction to negate the critical hit, reducing it to a normal hit.
This reaction may only be used once per round.

Notes: Bonus: Unarmored Armor Class, Immunity: Critical Hits, humanoid martial class with a minimum strength of 13 wearing no armor., Combat, Warding, Wristwear, Handwear