Man 2 Man M2M Ring Nitrile 3 Piece Set Sky Blue. Wear separately or together. Nitrile is the same material used to make gloves for emergency room doctors and nurses. Why Nitrile? Because Nitrile is 100% skin safe and hypoallergenic. Nitrile is also compatible and safe to use with all types of lubricants. Nitrile is stronger and holds its shape better than latex or rubber it stretches slightly to achieve maximum constriction without sacrificing comfort. Nitrile is available in a wide variety of colors, sizes and thicknesses. Nitrile M2M brands manufactured and packaged by PHS International. If you are looking for an inexpensive and versatile cock ring nitrile is the perfect choice. Climax control, prolong rings.