After receiving my attachment, I am mediately attached it to my littman classic to light stethoscope. After letting it charge a bit, I tested it on my wife. I could not believe the difference in the sound I could auscultate! It was like night and day. I use the attachment for students who are taking a blood pressure for the first time as well as listening to lung sounds for the first time I use it in the field all the time! I cannot believe I waited so long to get one.