The Littmann Cardiology IV stethoscope offers: Better audibility of high-frequency sounds. Tunable diaphragms on both the adult and pediatric sides of the chestpiece. Single-piece diaphragm that's easy to attach and easy to clean because the surface is smooth without crevices. Pediatric side of the chestpiece converts to a traditional open bell by replacing the single-piece diaphragm with a non-chill rim. Dual-lumen tubing eliminates the rubbing noise of traditional double tubes. Next-generation tubing is not made with natural rubber latex or phthalate plasticizers. Improved resistance to skin oils and alcohol for longer tubing life and less likely to pick up stains.7 year Warranty