Nothing beats a great pair of shoes! Crocs, an expert in the field, has designed the Classic Glitter Clog. With a black rubber upper, this design will be number 1 this season! From rubber on the upper level and a rubber lining to which is added a rubber insole.pour un rendu admirable. With no false notes, Crocs relies on rubber for the upper and rubber for the insole. These Crocs clogs have a wonderful purpose: to instantly enhance your look.