Fabric property tests in a laboratory setting do not always correlate to human comfort. To test how fabrics interact with the temperature and humidity of human subjects and their relative comfort value, we test a broad range of apparel, footwear and bedding with and without 37.5 Technology.
The temperature regulating fabrics with 37.5 Technology have consistently outperformed alternatives in testing at the independent Munich-based institute Inside Climate. For example, denim with 37.5 Technology had a lower combined temperature/humidity value by up to 5.3°F compared to denim with a competing technology. And when you add more layers, you get more benefits. The clothing system was cooler by up to 12.5°F when 37.5 Technology was used in both the denim pants and briefs underneath.