The next generation in electronic stethoscopy combining impressive acoustic amplification, electronic noise filtering and comfortable ergonomic design. The Adscope™ 657BK features: Amplifies up to 16x (24db) over traditional acoustic scopes Patented piezopolymer film contact microphone provides wider frequency response than acoustic mics used in competing models Three frequency modes: Bell (15-200Hz) for cardiac sounds Diaphragm (100-500Hz) for lung sounds Extended Range (15-1000Hz) allows the practitioner the widest frequency response 8 level volume control with level change tone Holds last mode and volume setting for convenience Auto-shut off after 3 minutes extends battery life Battery warning LED signals when replacement needed Binaurals fixed at 15º angle for snug aural fit Specially constructed Adsoft™ PVC eartips for the ultimate in wearing comfort and acoustic seal Lightweight and compact – weighs under 6 oz., measures just 28” Uses "AAA" battery (included) Made in Korea 2 year warranty