Square Pull Through Soap Disc Tool.  These fit a 32oz Dairy Carton or Juice container.  One quart size.  The hole will mount on the side. This way your can use bottles and extensions to center each layer.  The size is 2.66" by 2.66".  Each acrylic disc is cut with a laser. There is paper on both sides that peels off.  These do not come with rods. You will have to order those seperate.

Square Dairy Pull Through Soap Disc for Milk dairy Carton - PICK ONE