The Threefold represents balance in life, nature and the cosmos. The center of this symbol the "hub" represents unity of the three powers. The spirals at the end of the three outreaching arms symbolize an experience with the trinity that broadens the human consciousness and brings the soul back to the center - the core of understanding and awareness.
In other words "No matter how far we are separated, no matter how far we roam, no matter how chaotic life may seem, we are always united with the divine. “.
The pendant does come with a chain, but the loop should fit any 1.8mm diameter chain.