This economical acoustic Stethoscope is great for any human anatomy study for students. It has a diaphragm (larger, flat disc) and bell (hollow cup). Stethoscope is an acoustic medical device for auscultation, or listening to the internal sounds of an animal or human body. It typically has a small disc-shaped resonator that is placed against the chest, and two tubes connected to earpieces. It is often used to listen to lung and heart sounds. It is also used to listen to intestines and blood flow in arteries and veins. The diaphragm transmits higher frequency sounds like breathing and heartbeat, while the bell transmits low frequency sounds. It includes an optional earpiece and a supplementary diaphragm. It comes with a 2 page instruction. Not for medical use.