A keyboard support arrangement which includes both a main support pad for supporting a computer keyboard and an auxiliary support pad for supporting a computer mouse. The enclosure comprises a passageway system comprising a plurality of parts of different lengths. 8, and the pH of the composition, if necessary after adjustment with an alkali, is from 3. The temple piece is formed with a stud which extends into the hole so as to be pivotable about an axis defined by the stud, and which is formed with a plurality of second teeth. The energy source is fully differentially coupled with the resonant circuit at the input side.