This is great stethoscope enhancement for my Littman 3M cardio. I am pediatric cardiologist and I see patients of all ages from newborn to teenager. In my opinion, this is great for patients 5 and older but not for young babies and infant. somehow voice filter function is not great for young patient and auscultation is very noisy with loud respiratory sounds and can barely allow to better listen heart sound or any murmur. For older pediatric patient, this is great and very good sound quality and easy to identify subtle clicks or murmur on digital mode compared to analog. Blue tooth function to phone is good and gives nice phonograph. Phonograph is okay and not quite accurate. I had patient with pulmonary valve stenosis and murmur was easily over 3/6 but on phonograph, heart sounds have better tracing and actual murmur which was quite odd. Some patient and parents appreciate hearing abnormal heart sounds especially irregular heart beats on my phone in live audio mode. I wish this core digital Bluetooth directly connects to my Apple Airpods pro and much easier to listen.