This is a device study (while the device has been patented and cleared by the FDA, the indication of the use for Erectile Dysfunction has been yet approve). EXSTACY is a study to collect information on which patients who have trouble getting or keeping an erection rigid enough for sex (sometimes known as Erectile Dysfunction or ED) benefit from light intensity shockwave therapy (LI-SWT). LI-SWT is a form of energy transfer to the penis that has been shown to help some men with ED in studies over the past decade. This study will collect information about patients prior to treatment to determine what predicts a good outcome. The investigators hope that this information will help decide which patients are likely to benefit from LI-SWT and which patients should consider other treatments for ED.