All is good, pulse oximeter works just added battery pressed on put my finger and got the meter of heart pulse. very happy,received the product after a very long time of waiting and waiting... It's not the fault of the store but the corona lockdown and the delays of flights.
Very good quality. Easy to use. Compare just with pulsemeter. Fast shipping. Third picture isn't correct, because it is about frequency of display and a camera shot. Recommended