and work out on a treadmill. They gathered the comments of the testers and correlated this to the Ret values of the fabrics and came up with a Comfort Rating System. The testers could not perceive a difference in the garments made with fabrics within these ranges. So, a garment made with a 40 Ret fabric and one made with 55 Ret fabric did not have a perceivable comfort difference in use. Comparison of Test Methods Ret, A1, B1 and B2 test results do not correlate with each other. Two fabrics may have a B1 of 10,000gr, but one can be 10,000 A1 and the other 4,000 A1. It all depends on the type of coating or lamination and how it moves moisture. Typically hydrophobic coatings perform better than hydrophilic laminations on the Ret and A1 Test. And vice versa, the hydrophilic laminations will perform better on the B1 test. Technology Comparison Below is very generalized positioning of technologies. See also Breathing External links Breathability Comparison of Commercial Outerwear Shell Layers Textiles