When I first ordered these, I didn't expect too much. I figured, most grow lights on ecogrowhawaii.com majorly exaggerate how much light output there actually is and these won't work for actual plant growth -- but hey, maybe they'll be helpful for freshly transplanted seedlings that need reduced light intensity for a couple days to avoid transplant shock. Well, I was wrong! At the distance from the light to the top of the solo cups underneath it, I measured a PPFD of about 300, which is pretty decent for young seedlings: it'll promote growth without scorching them. It's about the same output I get with a certain popular brand of shop/grow light that most amateur gardeners use for seed starting, but with that brand it takes two lights to get the same output. Not bad! Peak output right underneath the panels measured at a PPFD of 2,052 μmol/m²/s, which is pretty decent. Definitely don't put your plants right up against these! Since they don't come with reflectors, you'll want to use Photone or a light measurement device to make sure your coverage is adequate, and maybe use a couple boards per shelf on your growing setup. This is also a good idea to check for consistency: I noticed the PPFD was 300 toward the edges of the board but closer to 250 right underneath, so the brightness may not be uniform with just one board. I like that the cord has a built in timer which can be set for 4, 8, or 12 hours. I will say though, I wish it had more customization because 14-16 hours is the sweet spot for many seedlings in my experience. But it's not too hard to hit the 4 hour button later in the day. Obviously I can't speak for the longevity of these since I've only had them a short while, but I'll update this if they give out prematurely. I also can't speak to whether these are truly "full spectrum" or not, because I haven't measured the different wavelengths (not sure if Photone does that, but if not, I don't even have the tool for it). I like that they come as flat panels, which makes them perfect for securing to the bottom of a shelf or cupboard, unlike the bulky overhead of using shop lights like many people do. I also like that they come with a set of 3M adhesive strips and also plenty of zip ties, giving you multiple ways to mount them to your setup. You get five light boards total, which isn't bad for the current price (under $50 at the time of review). Overall I'd say these are a great value and perhaps one of the best grow light buys you'll find on ecogrowhawaii.com right now.