A heat-shrinkable holder is disclosed for securing a plurality of articles. For instance, a component associated with the operating system may become registered for modifying input. The plurality of segments forms the nose cone. For controlling the wave front, a unit of dosed tilting of the wave front is introduced, based on the acousto-optic deflector, in the first embodimentin the measuring channel, and in the second embodimentin the probing channel. A convergence yoke for generating a beam-convergence magnetic field is disposed to extend from the large-diameter neck portion and surround at least a portion of the neck junction region. Each pair of conductors consisting of a trace of the first polarity and a trace of the second polarity may cross over each other at multiple crossover points.