Since my last vist, I have done extensive online research. Contacted Laser associations in North America, the world, and in Europe. The reason for a patient to have knowledge when approaching any treatment seems to me that you can ask the right questions, find the right practitioner, and make sure that the treatment will give the best results possible! I have been working with very generous scientists, researchers, and engineers. There are 8 parameters to consider. Companies like to sell their products. They use peak to peak which is a distorted power. Like stereo speakers you want RMS power, more exacting! Class IV is strong, great at relieving pain, but may cause damage if not adjustable down near a Class 3b & moved frequently. Dark skin patients must have laser 15 mm above the skin to prevent heating of skin! Finding a practitioner is the hard part. Got someone with 35 yrs experience who used a Class IV to treated a stroke survivor with burning pain in his leg, 5 years pain gone! Have counseling on 25th. Let you know what happens. If it fails then I will spent $4,950 for the best class 3b laser on the market that I had mentioned! They had listen to the practitioners and put that in their device. Dr. Paul Nogier I quess working on understanding acupuncture science came up with resonance frequencies for the body! Set at Nogier E 4,672 hz for the spinal cord and central nervous systems gets the best results.