16 necklace: falls around the base of the neck like a collar. 18 necklace: a common choice for women that will fall just below the throat at the collarbone. This length is popular for adding pendants which will hang over a crew neck.
20 necklace: will fall a few inches below the collarbone and allow a little more breathing room. All items are beautifully packaged in elegant jewelry boxes ready to be gifted.I'm happy to answer your questions. This item is made of silver, zircon and sterling silver.