3M Littmann Cardiology IV Black 27 Stethoscope. Outstanding acoustics with better audibility of high-frequency sounds (adult side firm pressure) * Tunable diaphragm: Hear high or low frequency sounds by slightly adjusting pressure on the chestpiece * Standard-Finish Chestpiece Black Tube Stainless Stem and Headset * Dual-lumen tubing: Two sound paths in one tube eliminates the rubbing noise of traditional double tubes * Next-generation tubing lasts longer and resists stains * Not made with natural rubber latex or phthalate plasticizers * Headset is easily adjusted for individual fit and comfort * Angled eartubes align with ear canals * Seven-year warranty provides greater peace of mind