Spiral screw extractor set, used to remove broken screws/bolts. See a video of a similar set in action here. Sizes 1 through 6.
Note: Size 6 is added in from a different set, and ends in a point rather than an indent like the rest of the set.
Victoria Tool Library
http://victoriatoollibrary.org/
750 Fairfield Roadhttp://victoriatoollibrary.org/
Victoria, BC, V8W 2H1
Canada