Amplifies sounds up to 18X (24dB) Noise-filtering contact microphone eliminates background interference Eight-step volume control with last-setting memory Cardiology headset with bilumen tubing and stainless-steel binaurals Multifunction button controls the frequency mode (bell or diaphragm) and the volume (eight levels) Backlit LCD display powers down automatically if not in use Rechargeable Li-ion battery twenty hours of continuous use on a full charge High-impact thermoplastic housing withstands drops bumps and other contact Measures 30 inches and weighs 175 grams Contact microphone measures 7 mm in diameter suitable for use on any size patient Includes three pairs of Adsoft Plus snap-on silicone eartips two small and one large