These artistic gems are made from 100% Borosilicate glass, and are designed to bring pleasure to PC muscle exercises. Once inserted, they will help strengthen the Kegel muscle, while providing rippling effects of stimulation. At a larger 2'' x 1.25'' (51mm x 32mm) in size, these eggs are a delicious, yet discreet item. Crystal premium glass eggs include a silk storage bag and a detailed instruction manual (that outlines PC muscle exercises designed to give pleasure and maintain healthy muscle control).