This round disc has an astrological constellation hand drilled through its face. The larger holes representing a larger star cluster within the constellation. The Constellations are based on a Swiss calendar from the 1900's. This one is Aquarius and is hand stamped "Aqua" on the back. The chain length is 20" and is made of brass. The dimensions of the brass pendant are about 1 1/4" in diameter or 32 mm.