On one hand, it optimizes data quality in bright daylight, and on the other hand, it allows full customization. The material is based on kinesiology tape (physio tape) to ensure comfort but it is enhanced with light-blocking fabric.
Optimizing data quality
It is not needed to wear the patch during indoor training, or grey outdoor days. We recommend wearing the patch when you are immersing the sensor directly in sunlight. This is needed to prevent interference from ambient light and ensure data quality. You stick the patch directly to your skin and place the sensor (with the logo in the same direction) over the marked area on the patch. This might seem strange, but the sunlight is actually received via your skin. You can wear the patch for up to two weeks when placed directly on the skin, even during intense training sessions including swimming. This is similar to Kinesio tape
Allowing full customization
When it is hard to strap your sensor over the area of interest, you can use the patches as adhesives to stick the sensor to your body. Depending on the impact of the activity you can use 1-2 patches per sensor. The patches provide the freedom to place the sensor anywhere on the body.