Green Lazor help

[DrBanxon]

I've wanted this green laser pointer from ThinkGeek for a while now but its price has always been way too steep for me.
I went to eBay to see if maybe they had $50 ones, and I found hundreds for around $20, such as this one. They both have the same specs, 532 nm wavelngth, output power of 5mW (Class IIIa), and stuff like that. Thins is, I don't know what any of this stuff means :[
Can someone tell me what the difference between these two products is other than ~$60? Thanks

Sorry if this is in the wrong section >.<

 

[Vayne Mechanics]

mW = Milliwatt
nm = nanometers

You don't really need to know what those specs are for, they're just there so it sounds cool to the average person. In reality, all green laser pointers would have a wavelength of 532 nm. They're pointless specs that you only really need to worry about if you're studying the visible spectrum.

 

[DrBanxon]

mW = Milliwatt
nm = nanometers

You don't really need to know what those specs are for, they're just there so it sounds cool to the average person. In reality, all green laser pointers would have a wavelength of 532 nm. They're pointless specs that you only really need to worry about if you're studying the visible spectrum.

I see... But which one should I get?
I don't want to waste $80 on something I can get for $20...

 

[Vayne Mechanics]

The $20 one looks like the black version of the ThinkGeek pointer, and it's cheaper. If you don't think you should be spending $80, then don't. Go with the $20 one.