Oximeter

This is the first time I heard about oximeters. It is a medical devise that indirectly measures the oxygen saturation of the person's blood. There are different types of oximeters. There's this one called finger pulse oximeter. This type has various models available. Each model has a couple or more unique features that would certainly fit your requirement. Another type is the hand held oximeters with alarm and memory that can store up to 72 hours. The devise is actually a good-to-have tinhg; especially to those who are very health conscious or those who needs to monitor their health regularly.