*3MTM Littmann© Stethoscope's proprietary ambient noise reduction technology which eliminates  on average  85% of distracting background noises *Provides extra listening power when a heart  lung or body sound is especially faint *Record multiple sounds in one patient and compare them or save up to twelve 30-second sounds; 12-track recording capabilities  *Listen to sounds at half or full speed; *Visualize your patient's heart sounds as a phonocardiogram  * Transmit the sounds utilizing Bluetooth© technology software included FREE with purchase * 3MTM Littmann© Snap-Tight Soft Seal Eartips  *Made in the U.S.A. *Warranty Period  2 years