I haven't personally used them, but I heard that they were decent. I'm always worried about buying items that I haven't read up on much or that seem too inexpensive.
http://www.hedman.com/pages/chikara/chikara-tech.html
They're made by Hedman. That company has been around for a while. They don't make them for the B16 apparently.......
Are those the ones with their PowerPlus technology?