These fit a 3" PVC pipe with no liner.  YOu get all 3.  If you need the center hole a different size let me know.  Also I can make some for the Soapers choice silacone molds that are 2.75"  Just make sure to tell me its for the smaller molds.  A all thread rod will fit in the center it you do not want to use strings.  The Hold is designed to fit 6/32" to 1/4" or #6-32, #8-32 Metric All thread rod. Can be found at your local hardward store.  Each acrylic disc is cut with a laser. There is paper on both sides that peels off.

Pull Through soap disc tool Flower Tools and Bubbler set of 3

Size in Inches