Abstract: An ultrasonic probe for generating shear waves in a test piece, having a liquid-filled cell housing a transducer. The cell has a window for application to the test piece and the transducer is pivotable to provide variable angle of wave incidence at the window. An external scale, calibrated in angle of refraction of resultant waves in the test piece, permits of pivoting the transducer for the corresponding angle of incidence by way of a mechanical linkage. For a given wave velocity for a known test piece material (steel and aluminium is chosen) and for a given liquid filling, the linkage geometry is predetermined. Reflected energy within the cell is attenuated by bristle bundles.