Has anyone used them? Any good?

 

How do they work?

 

I think they work the same as any of the check ball type bleeders. They have a spring and check ball inside them allowing them to bleed fluid off but not allowing reverse flow back to the brake lines.

 

yup...that's how they work

and they do work. open them up a quarter turn...hit the brakes a few times...tighten them back down. or you could spend the twenty bucks on the "magnetic brake bleeder kit" at autozone and just do an easy bleed that way too. it works on gravity. i bled my jeep with it and it's worked fine.