The Belun Ring is a pulse oximeter that is worn like a ring. Data are collected while the wearer is sleeping and transferred to the docking station when the ring is placed on it. The legs on the ring ensure that the sensor stays at the correct spot during the night and that the ring does not rotate. Thanks to its elegant form, black colour and glossy surface, which is inspired by a gemstone, the pulse oximeter looks more like a piece of jewellery and less like a medical product.