THESE HAVE A 16G POSTS ON THESE WITH A 5MM BACK DISC.  THESE HAVE A REAL STERLING SILVER 4 PRONG SETTING FOR THE LIGHT PURPLE AMETHYST STONE.  YOU CAN CHOOSE BETWEEN A 1/4" INCH  OR 5/16" INCH (8MM) POST LENGTH. REAL HIGH QUALITY AND fit nicely.   * Excellent Quality * * Brand New * THIS AND ALL MY JEWELRY IS NEW AND HAS NEVER BEEN WORN.  THE PICTURE DOES NOT DO THIS PIECES JUSTICE.  SL 050 AM AMETHYST (SIZE)