Does anyone know how to measure real power output for the laser?
I want to buy 8 watt laser
https://www.ebay.com/sch/i.html?_fro...laser&_sacat=0
but have a big concern if they are rated and have real power output.

there are many supplies in google: https://www.google.ru/search?q=8+wat...hrome&ie=UTF-8
so how to choose the right one?
any ideas?