Price (new): $60
Cell type: Selenium
Measure type: Two Color-Temperature
Years ago I decided that the solution to all the problems in my life was to buy a color temperature meter. I'd meter everything and then correct the color to balance to daylight. I even started collecting the filters to do it, and I bought this on eBay (actually I bid both on this and the color temp attachment to the Luna Pro sbc, and to my horror I won both auctions). I've used it less frequently than I thought, but occasionally it's very handy. Since it's Selenium it doesn't need a battery. It's direct read and the filter conversions are in the leather case, so it's a lot faster and less hassle than rigging up the Luna Pro sbc.
What you do is look at your light source and put the meter between it and your eyes, so it sees what you see. Push the button and the meter needles stops somewhere on the scale. You can read the temp in degrees Kelvin and in Gossen's special scale; using the later, you can look at a little cheat sheet that tells you which combinations of filters to use to correct to Daylight film. Neat little rig.
This is a two-color meter, like the sbc attachment. Two color means it measure red and blue, whereas the better (and far more expensive ones) measure red, blue and green. Two-color is good enough for what I do, and even three-color meters still run afoul of flourescent lights, so I never felt the need to upgrade.