This is a Devotional Scapular. Devotional scapulars are objects of popular piety, primarily worn by Roman Catholics, as well as some Anglicans and Lutherans, designed to show the wearer's pledge to a confraternity, a saint, or a way of life, as well as reminding the wearer of that promise.
To wear a scapular, one rectangle hangs over the chest of the wearer, while the other rests on the back, with the cords running over the shoulders. It should fit anybody.
This scapular is made of 100% wool.