Feature 1.Easy to Operate&Using, the users get the using method easily. 2.Small size, Light Weight, Portable Design. 3.The rich colors to meet aesthetics of various people. Single-Head Chestpiece 1.Delicate texture 2.Comfortable hand 3.Anti-collision design 1.Exquisite Technology, Smooth Texture. 2.Exquisite package, Convenient Storage Read more It is used to collect and amplify the sound inside body organs like heart, lung, arteries, vein, etc., which is applicable for use in hospital, clinic, examination institution, ambulance, home and camping rescue, etc. Function： Measuring the sound changes of heart, lungs and other organs in animals. Accessories User Manual 1pc Performance： Frequency response curve attenuation limiting value of sound attenuation stethoscope as following： 100 Hz ~ 500 Hz as the reference of the testing sound source: Outer diameter of auscultation head ≤ 35 mm, damping ≤ 30 dB Outer diameter of auscultation head > 35 mm, damping ≤ 16 dB 500 Hz ~ 1000 Hz as the reference of the testing sound source: Outer diameter of auscultation head ≤ 35 mm, damping ≤ 25 dB Outer diameter of auscultation head > 35 mm, damping ≤ 20 dB The elasticity of ear hook is appropriate, pulling the ear tube, the distance of two earplugs is 140mm, the range of elasticity value is 1.4N-5.0N The elasticity of ear hook is good, pulling the ear tube, the distance of two earplugs is 300mm, the deformation distance after recovery less than 10mm The average thickness of tubing is greater than 1.5mm, good sound of insulation and transmission.