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 chest piece. 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 ear tubes align with ear canals. Seven-year warranty provides greater peace of mind, Non-chill bell sleeve for greater patient comfort.