How exactly do they work?That pretty much sums it up.I've always bled my brakes with 2 people so i'm not sure of how they work.Thanks for any replys....

 

I have them on all four corners. It's a bleeder screw with a spring-loaded checkball and a coating on the threads that prevents air from entering the system. You just back it out a quarter turn and pump the brake pedal 'til you don't see air bubbles, then move on to the next one. I think they're great, since I do all my work myself.

Some magazine article recently described a way to do it yourself with regular bleed screws though. Apparently you just back out the screw a tiny fraction, enough to let fluid out, but still give some backpressure when you depress the pedal.. I dunno, but since the screws were only $20 for all four, it works fine with me.