If you have a VR-3 with an external cell and a plastic bag, you have an oxygen analyzer..... no need to buy their kit.
PP02 at 1 ATMA = %. Just learn to move the decimal point two to the right...
Seriously, the VR-3 like *any* other PP02 sensing computer is just an 02 analyzer with extra software included. I made a nice little delrin adapter that the P-Connector probe that I use in my rebreather fits into, that then plugs into any female DIN port for analysis, but it's just a fancy substitute for a plastic baggie. You *certainly* don't need to buy extra hardware and maintain a second sensor to use it as a viable 02 analyzer. The VR-3 is a great piece of equipment. Color screen a must for older eyes....
Dave Sutton