Lasers are more powerful devices than class 1 and 2, with a maximum output power of 5 mW or 5 times the AEL of Class 1 products. Laser beams from these products exceed the maximum exposure allowed for accidental viewing and can potentially cause eye damage, although the risk of injury remains low. The Class 4 laser has an output power greater than 500 mW (half a watt). There is no upper limit to the output power. Class 4 lasers can cause eye and skin damage and can also be a fire hazard if used at a high enough output power. Lasers used in many laser displays, green laser pointer surgery, and cutting metal can be in 4 categories. Lasers, especially those used as astronomical laser Pointers, have experienced rapid development in the past few decades. A large boxed unit reserved for the observatory, requiring a high level of maintenance, power consumption and cooling equipment, is now available in a convenient and portable handheld form.
At the same power output, the green laser is always brightest, meaning that the 100mW green high powered laser designator is more than 7 times brighter than the 100mW laser of other colors. Now, that doesn't mean that colors like blue, red, purple, or yellow are impractical for astronomical purposes, because they're also fully utilized. You only want to think about getting the same brightness for non-green lasers, you need to buy a more powerful pointer laser with a higher power output. Any other color at 100mW is still very bright (definitely for night use) and even comes with some sculpting features.