generally a shaded marginal portion 20 which is gripped between the cavity blocks and a similarly secured tab portion 21 of sufficient length to extend beyond the outside edges of blocks 10 and 12 when assembled together a central vibratory portion 22 of the bending member is cut free of the member proper by two slits 23 extending through the thickness of the member this permits the vibratory center portion 22 to be free at its ends on one side of bending member 11 between slits 23 is placed a plurality of transducers preferably piezoelectric strips of a material such as barium titanate these strips are cut with a length to width ratio varying from approximately 4 1 to 6 1 and have a thickness of approximately 10 mils the length of the transducer strips 24 is preferably approximately the length of the slits 23 which can in turn vary according to the amount of bending deflection desired within cavity compartments 15 and 16 the piezoelectric material is preferably selected for maximum bending as is shown in fig3 transducer strips 24 extend beyond the upper and lower limits of compartments 15 and 16 but may be shortened to less than the edges of the compartments proper adjacent bending member 11 the relatively large length to width ratio is desirable for the piezoelectric strips in order to maximize bending of central portion 22 about its longitudinal axis the piezoelectric material is mounted for expansion in the thickness mode only and when energized will tend to bend in a dish shaped manner the narrow width of each transducer finger tends to minimize the effect of the dishing and thus produce single axis.