This is what it looks like -
This is what it does - It's a cover you place over your lens, you take a photo towards the main light source in the area you'll be shooting and then save the exposure as your custom white balance reference.
I realize this might not make sense so I'll show you what it does.
The photo on the left was taken using my cameras auto white balance setting and the photo on the right was taken using the custom white balance setting achieved by setting up the reference exposure with the baLens. Notice how the photo on the left has a yellow cast to it?
Next I took it outside and got some nice photos of one of my cats.
So fun! I can tell a big difference in the color of my photos, they're much "truer to life." And it's so handy, it just takes the place of my lens cover. I must say I'm impressed, not only with the baLens but that Tim thought to buy it for me when I didn't even ask for it or knew it existed!