Maker: Quantum Instruments
Model: Calcu-Flash II
Price (new): $125 (1981) - $195 (1999)
Cell type: Silicon blue
Battery: Energizer 357 or equivalent
Measure type: Incident flash
Quantum Instruments in New York specializes in studio lighting. Their original Calcu-Lite was one of the first digital meters to show up on the market, and it was a big hit. The great advantage of getting rid of the mechanical meter movement was that you removed the weakest part of the meter; if you dropped it, there was a good chance the meter movement would be broken or knocked out of calibration. As someone put it on a cinematography forum: if you drop a mechanical meter, it could be off 2 stops and you wouldn't notice until you realize your exposures are consistantly bad. If you drop a digital meter, you either get obviously crazy readings or you get nothing at all, and you know immediately it's broken.
Quantum tweaked and updated the Calcu-Lite several times with different model names, but the basic configuration remained the same. This is (I believe) the last version. The silicon cell sits under an interchangable cover so you can go back and forth between incident and reflected light. It's capable of measuring flash and integrating it with ambient readings, and it has a memory so you can measure contrast ratios. Best of all, you can still buy batteries for it.
As they say on the British tv show Top Gear: It's brilliant. It's not intuitive—I had to read the manual to figure it out, but once I did it it worked fine. It's nicely designed, can be used one-handed, it fits beautifully in its case so you can use it without taking it completely out (unless you want to physically connect a sync cord). It looks as if it were designed by people who actually use these things.
I was surprised at how inexpensive and easy they are to find on eBay. Mine came with all the standard accessories and appears to be very gently used, and I paid about $30 for it. Considering that flash meters are one of the few types that haven't been made obsolete by modern camera meters, I would think the resale demand and values would be higher. My Wein WP1000 is similarly undervalued.