The MAX86916 sensor features a 200-micron glass cover, but it is not rated for water protection or high pressure; therefore, it should be encapsulated to prevent water ingress and protect it from pressure. For the transparent material to encapsulate the sensor, refer to application notes on the opto-mechanical integration of heart-rate monitors in wearable devices (see below). Algorithms for calculating SpO2, heart rate (HR), heart rate variability (HRV), blood pressure (BP), and respiration rate (RR) need to be developed if the sensor is to be placed on the temple of the subject. The sensor can withstand temperatures ranging from -40°C to +85°C, but pressure testing has only been conducted up to 6 kgf at a flat surface for 8 seconds, which is insufficient for diving applications (diving pressures would be much higher than this and for an extended period of time); thus, the encapsulation method must handle higher pressures.
Please refer to these guidelines for selecting the sensor cover: