American Diagnostic Corporation (ADC) 657 Electronic Stethoscope - Manual (Page 10)

5. Specifications
Power supply: 1.5V (AAA Battery)
Electric current supply: 20mA (max)
Battery life: 150 hours under continuous power on
(approximately 3000 measurements at 3min/per.)
Weight: 6.17 oz. (175 grams)
Length: 29.1 in (74cm)
Frequency: Bell (15-200Hz)
Diaphragm (100-500Hz)
Wide/Extended Range (15-1000Hz)
Operating environment
• Temperature: -4°F to 140°F (-20°C ~ 60°C)
• Humidity: 20 to 90% Relative humidity
Storage environment
• Temperature: -4°F to 158°F (-20°C ~ 70°C)
• Humidity: 15 to 95% Relative humidity
Regulatory standards
EN 60601-1 (1988) Medical electrical equipment, Part 1: General requirements of safety
EN 60601-1-2 (1993) Medical electrical equipment, Part 1: General requirements Section 1.2
Collateral Standard: Electromagnetic Compatibility