Mental Tools - Any good?

Hello, wanted to get feedback from any traders, who have used or tried any type of tools such as a stress monitor. The idea is to know what state your mind is in, so you can perform and stay "in the zone"

there are a lot of products out there, a lot of traders as we know use music to keep them in the zone, and various brain wave CD's that work extremely well, but I wanted to get feedback from others, on things such as this:
http://www.signs-of-stress.com/stress-monitor.html

I am NOT trying to endorse this, just wanted some feedback if anyone has tried this, and if so, did they find it to be useful...

appreciate your comments/thoughts...

I think that buying biofeedback equipment itself will make little difference because in addition to the equipment you also need actual training how to change your state of mind. I mean, biofeedback equipment only will report that you are currently under high stress, it won't make you more relaxed. When I have loosing position I know that I am stressed even without stress monitor - I just feel it - but I don't know how to relax. In addition to purchasing the equipment you will need to find research center that can train you how to use it, and it will probably will cost a lot of $.