Outstanding acoustics: The highest in Littmann mechanical stethoscopes. Tunable diaphragm: Hear high or low frequency sounds by slightly adjusting pressure on the chestpiece. Dual-lumen tubing: Two sound paths in one tube eliminates the rubbing noise of traditional double tubes. Headset is easily adjusted for individual fit and comfort. Angled eartubes align with ear canals. Includes special procedures adaptor for pediatric or neonatal auscultation.