I have 3 sizes. Used to be distributed by Christy's with the name "Socket Saver". I've used them for over 5 years...maybe closer to 10. You need to have the right approach angle and room for a drill.
I heard Christy's stopped selling them (www.tchristy.com
) so I bought a couple extras.. I did get one stuck in a tee once when the screw came loose.
I've also used a heat gun to extract broken stubs... carefully.