A hand-tool consisting of a reverse-telescoping assembly of various sizes of torx or allen wrenches. This would allow several sizes to be available in a smaller tool than the discrete fold-out sets, more convenient than discrete socket bits, and be more durable than the spring loaded pin "universal" tools (as these types of screws tend to need higher torque.)
The collar would contain a mechanism to remove support from the larger sheaths such that they can be retracted to expose the smaller bits, but signifigant axial pressure can be still applied. The allen wrench version would also allow for the larger sheaths to be extended for light-duty use as a socket.
Though a single-ended tool would probably not be able to service all sizes and remain durable, with a shiftable handle, even sizes on one end and odds on the other the tool would most likely be capable of sustained use without degradation. Of course, that last statement is predicated on the use of quality material and precision manufacturing.-- skids, Apr 23 2006 U.S. Pat. Nos. 2,735,325, 2,822,714 and 3,127,798 disclose telescoping allen wrenches.-- ldischler, Apr 23 2006 excellent +-- xaviergisz, Oct 15 2010 random, halfbakery