HFS-5 economical heat flux sensor for heat transfer measurements provide accurate readings, high sensitivity with fast response times. This sensor is rugged and economical. It is ideal for R and D applications ranging from aerospace, industrial processes to building sciences, energy efficiency of thermal systems, heat transfer education, wearable technology that detects calorie burn applications. It has minimal thickness while still maintaining excellent sensitivity. This heat flux sensor is flexible enough to be easily attached to round surfaces.