The American Federation of Human Rights Official Pendant.
This is the larger version.
The Square and Compass is set with a 5 pointed star, and inset into the star is the hebrew "YOD" symbol, which is the first letter of the ineffable name of G-D.
This pendant is about 1 1/16" in diameter and 1 5/32" tall. Each is accompanied with an 18" spiga style chain, small descriptive pamphlet, and a genuine blue velvet gift box.