I have one
I have one of the green lasers
. It has a max output of < 5 mw & wavelength of 532 nm. It is quite bright and dangerous to look at directly. We use them at our astronomy club star parties and demonstrations. When someone says what are you looking at you can shine the laser at the star/planet and it clearly shows a green trail up to the object. Some also mount it on the scope and can mark what it is looking at. We are careful to not point them at planes or helicopters.