Use Contact when you want to have the electricity running through the body.
Use Plasma when you need to kill something very aggressively.
Use Remote when you need to be away from the devices, but still want the benefits of running frequencies - and maybe more than one different program running at once to assist with different maladies.
Use Cold Laser when the issue is rather surface, or when you want to focus healing on the nose or ears - since contact should not be used above the shoulders, etc.
Again, often there isn't one mode only that may be used for any specific area or malady. We often use many remotes and one other mode at the same time. Just find what works for you. Some people use nothing but remote and have great effectiveness for general maladies, although I wouldn't recommend this for very serious or aggressive issues.
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