Irwin 53226 10 Piece 1/8-Inch to 13/32-Inch Hex Head Multi-Spline Screw and Bolt Extractor Assortment in Plastic Case
Professionals all say the same thing. It's tough to get a good grip on a frozen fastener.  Rounded-off or broken heads, snapped studs, damaged socket screws and fittings.  Here's a great set of extractors!  These are made for higher torque applications, with multiple strategically placed splines.  The extractor turns your socket or flat wrench into a powerhouse tool.  Use it when space is limited, or if you need to get a good grip without drilling a deep hole in the fastener.