Class 3 covers output power from about 1 milliwatt up to 500 milliwatts (half a watt), and it's split into two subcategories with very different risk profiles: Class 3R and Class 3B. Class 3R (sometimes still called Class 3A or IIIa under older U. regulations) is the lower-risk. Most laser products are required by law to have a label listing the Class. It will be listed either in Arabic numerals (1 2, 3R, 3B, 4) or in Roman numerals (I, II, IIIa, IIIb, IV). It sits in the middle of the laser classification system, above the low-power lasers found in barcode scanners and basic laser pointers, and below the high-power Class 4 lasers that can burn skin and. In general, magnifying glasses increase the risk of a widely diverging beam (e., those used in open-beam telecommunications systems). A Class 3 laser system may be hazardous to the eye under direct and specular reflection viewing conditions, but the diffuse reflection is usually not a hazard, it is not a hazard to the skin. In many cases, it is unnecessary to make use of MPE's directly. The experience gained in millions of hours of laser use in the laboratory and industry has permitted the development of a.
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