Interesting concept and essentially used what amounted to a one compartment decompression model. Rather than using a computer model it used a filter to control the passage of air from the pressurized side of the meter to the side with the needle. The longer and deepr you were down the farther the needle went.
I never actually knew anyone who used it, the crowd I dove with was just too skeptical, and in this case with good reason. They come up fpor sale frequently on E-bay and go for pretty reasonable money, $25 to $50 or so, and are available in both both US and Metric versions. The US versions seem to bring a little more money at auction.