Technical Specifications: 1. SpO2 Range: 0-100% Accuracy: ± 2% at 70-100%; <70%, undefined Resolution: 1% 2. Pulse Rate Range: 30-250bpm Accuracy: ± 2% at 30-250bpm Resolution: 1bpm 3. Power Requirements: AC power supply: 100-240VAC, 47-63Hz Battery: Four standard AA alkaline or Ni-MH batteries. 4. Battery life: Alkaline Cells: 20 hours Ni-MH Cells charging time: 6 hours 5. Environment: Operating Temp.: 0 to 45° C Storage Temp.: -20 to +60° C Relative Hunmidity: 30 to 95%(Operating), 10 to 95%(Storage) 6. Equipment Classification Type of Protection Against Electric Shock: Internally Powered. Mode of Operation: Continuous. Degree of Proctection Against Ingredd Of liquids: IPX1, drip proof. Degree of Mobility: Protable. Degree of Protection Against Electric Shock: Type BF.