Be very Careful if you buy one of these lasers.
There is a reason the FDA has classified them, "Class IV".
Class IIIa & IIIb lasers generate no heat, and are VERY SAFE. They are commonily referred to as"Cold Lasers". They can be used for hours at a time, without generating heat or causing harm to your patients.
Class IV lasers are VERY DIFFERENT. If you use one of these devices for several minutes, you could cause serious harm to your patients. Most Class IV operating guides, warn about prolonged exposure. They consider a few minutes, prolonged exposure.
If they were "Cold Lasers", why the warning? "Cold Lasers"
do not produce any heat and can be used for any duration of time.
Here is a definition of a Class IV laser from Wikepedia:
