Oxygem measures the level of oxygen in the user's bloodstream using built-in sensors that measure the levels of red and infrared light that pass through the finger. Changes in the amount of light absorbed correspond to the levels of oxygen in the blood. The device alerts the patient with updates on the ring interface and a corresponding phone app. In cases of emergency, the device is programmed to notify local ambulance services of the whereabouts of the wearer. The product allows people with sickle cell disease to self-monitor the levels of oxygen in their blood, reducing the risk of infections and death. Available in three different sizes – small, medium and large – the smart ring is made to appeal to all ages and genders, and features a wide selection of colour options.