You have specified the measurement of oxygen saturation as the "main function". This function is important for me. Now I bought the device today and unfortunately I can't find a way to access the function. Three questions: 1. is it correct or not? 2. if it is true: What have I missed? 3. if it is not true: What is your fair offer (I have already destroyed the packaging material. The reason I'm quite upset is that this is the second time I've found that the information on your website seems to be inaccurate when making a major purchase from Digitec/Galaxus.