Eko core digital stethoscope attachment. Comes with the regular and pediatric size attachments/extra tubing. Fits my husband's cardiology IV but fits with a large variety of single lumen stethoscopes and not just littman. Bought this for my husband and he used it at work for less than a week before deciding it wasn't for him. This is virtually brand new and has zero flaws. This has some significant amplification and Bluetooth for people who may have hearing aids. You can record your chest assessments and play them back through the app as well. If you have any questions let me know. Willing to accept any reasonable offers.