Information request on the popular 301 green lasers



Apr 25, 2017
I'm new to lasers and know little about them aside from the fact the light is coherent and also what I've learned recently-- that a green laser at about 100mW has output of about 61 lumens, is narrower than red but is wider than blue when the focusing lens is removed, and that green is the brightest component as seen by cones and blue by rods.

I've seen that the Laser 301 is a popular and common laser which is cheaply available on Banggood. I found three links:

(Moderators, my intention with the links is merely to get advice, not promote a vendor. But if that is inappropriate, please advise giving a little space and I will quickly edit out the links of this post.)

I'm a little leary of buying something that might not necessarily be accurately represented but I think these lasers are all the same (just branded differently) and are between 150-200mW in power. Is either of the three lasers a better build in your opinion?

These 301 type lasers all have a focusing knob. My other question for people familiar with this green 301 laser is, how many millirads or degrees can the knob defocus (fully widen) the green laser beam? I'm thinking in terms of maximum, full beam span (not half angle--just to be on the same page). I'd be happy with an approximate distance to wall measurement and the corresponding diameter of the dot/spot.

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