When I first in need of finding a blue laser pointer to do experiment in my lab, I am just considering whether it can be continuously lighted up in my work. However, it is quite hard for a laser pointer to make even more than 5 hours blue laser light emitting in operation. I changed my mind to choose a dot projecting blue violet laser alignment.
This blue violet alignment laser has a bit shorter wavelength of 405nm. It is specially made in type of laser module, and have a power supply. I just think it is much better. It can be continuously operated, thus it might fulfill my requirement. As a result, I confirmed the following technical data from Berlinlasers:

What is the selected output power of laser alignment?
On considering of laser safety, I finally chose this series alignment laser pointer lower than 30mW. High output powered laser device might burn my sample.
What is the size of laser spot at 20-30mm?
When I operate this 30mW laser alignment tool, the laser dot diameter is 4.23mm at 30mm. It is just fulfill my need exactly.
How about the stability of beam intensity of blue violet dot projecting laser alignment?
The primary output power is 30mW. After 5 hours continuous test, the laser alignment just keeps its stable output power of 32mW to 33mW. The blue violet dot is just keeping stable.
When I operate this dot generating alignment laser pointer tool, its blue violet laser beam is always very stable and bright. I just want this dot measuring tool as a recommendation for other users. I hope it might be helpful. This laser alignment also gets quite wonderful thermal emitting. It is just making quite nice dot measurement result in my work. I hope my test is helpful for anyone else.