Looking to get something cheap but effective on Alibaba. Overwhelmed! What specs should I be looking at?

So, I’m really only interested in red light for acne and fine lines on my face, maybe NIR, but for red light I know it should be around 660nm wavelength.

Besides wavelength what should I be looking at/asking about to know whether it’ll be effective? Overall lamp power? (The one I’m looking at says 20w?) Number of lights? Number of chips? (Is that important?)

Someone said it’s a bad sign if the device doesn’t have a built in fan- is that true?