it's pretty important to point out that a key switch and interlock plug does *not* make your laser pointer legal/FDA compliant.
from
U S Food and Drug Administration Home Page:
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Does FDA have a mandatory limit on the power emitted by laser pointers?
Yes. Laser products promoted for pointing and demonstration purposes are limited to hazard Class IIIa by FDA regulation.
21 CFR 1040.11(b) and 1040.11(c), limit surveying, leveling, and alignment, and demonstration laser products to Class IIIa. This means that pointers are limited to 5 milliwatts output power in the visible wavelength range from 400 to 710 nanometers. There are also limits for any invisible wavelengths and for short pulses. Pointers may not exceed the accessible emission limits of CDRH Class IIIa or IEC1 Class 3R.
Are Class IIIa laser pointers dangerous?
Class IIIa or IEC Class 3R lasers can be dangerous. Class IIIa lasers can cause temporary visual effects such as flash blinding, which could distract or startle the person exposed. The risk of injury is very small when Class IIIa pointers are used responsibly because natural body motion of a person holding the pointer or motion of a person who might be exposed makes it difficult to expose the eyes for a long period of time. People also have a natural aversion to bright lights and are likely to close their eyes and turn their heads if exposed.
What are class IIIb lasers and are they dangerous?
Lasers that emit between 5mW and 500mW output power are in Class IIIb or IEC Class 3B. Class IIIb lasers cannot legally be promoted as laser pointers or demonstration laser products. Product labels and user instructions must describe the hazard classification of the product and its output characteristics.
With any laser product, the potential for injury depends both on the product itself and how the product is used. Higher powered Class IIIb or IEC Class 3B lasers are dangerous and can cause either temporary visual effects or an eye injury.
What is the problem with more powerful Class IIIb lasers being promoted and sold as pointers?
Class IIIb hand-held lasers are too dangerous for use as pointers or amusement articles. Furthermore, promotion of Class IIIb or IEC Class 3B products for pointing or amusement violates FDA requirements and United States law. Manufacturers of such products may be required to repair, replace, or refund the purchase price of violative products distributed in the U.S. These products are also subject to detention and seizure by the U.S. Customs and Border Protection when imported.
Irresponsible use of more powerful laser pointers poses a significant risk of injury to the people exposed. Persons who misuse or irresponsibly use lasers are open to personal liability and prosecution.
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i'm not suggesting you are or will be irresponsible with it, but i wouldn't be using it with impunity because you think it's legal.