Sign up for The Hardness Factor newsletter   Learn more about the 6-week Hardness Factor™ program that will change your sex life forever! In Case of Emergency Only! The Hardness Factor 4-Day Insurance Policy	Home / Partners of The Hardness Factor   Uroan 21 The Digital Inflection Rigidometer (DIR) is a unique diagnosis device used in specialist centers of sexual medicine to monitor erectile quality. By simply pressing a sensor against the tip of the penis, buckling force is registered in a numerical value (grams of axial rigidity). This simple reading provides an indication of the penetration capacity and allows the doctor to monitor erection levels and decide whether there is room for improvement of hardness.