Despite its glass-like appearance, the red ice is made of an award-winning, fda approved, medical-grade plastic which is useful as a replacement for glass because it does not break.like the others in the progasm family, the large red ice features a round perineum tab and also boasts a kundalini "k-tab". the "k-tab" adds sensations up and down your back that are complementary to the sensations from the prostate.mobility is a key to success with our products, and despite its size the progasm moves inside the man's body to provide a robust prostate masssage for incredible pleasure.round perineum tab designkundalini "k-tab" provides additional sensationshas size, but is very mobilefor advanced and experienced users