Superior acoustical performanceFeatures up to fourteen fimes the amplification of conventional Littmann stethoscopesThree frequency response modes to choose from for optimal heart and lung auscultationErgonomically-designed chest piece is sized for adult or pediatric patients Volume control dial, mode selector button and non chill rim.Includes soft-sealing ear tips, anatomically correct headset, one AAA alkaline battery for 40 hours of continuous use.