Esperanza OXYGEN ECO001 Finger pulse oximeter

Quick overview from the supplier:

Finger pulse oximeter Esperanza OXYGEN ECO001, Big font OLED Display, SPO2 measuring range: 35-100%, Accuracy: 70% - 100% ± 3%, Pulse rate: Measuring range: 30bpm - 240bpm Parameter accuracy: ± 2bpm or ± 2%, Power supply: 2 *AAA batteries(1.5V)