Abstract: An apparatus for ultrasonically testing a part uses a transducer which emits sound waves to flow through a water column into contact with the part. The housing has sidewalls, a top, and a bottom, defining a reservoir. The transducer locates in the reservoir and points downward toward the bottom. A collar extends upward from the bottom in alignment with the transducer. The collar has an open upper end spaced a selected distance above the bottom. A tube mounts in the collar in alignment with the transducer. The tube will slide vertically relative to the collar. The lower end of the tube protrudes through an aperture in the bottom for contact with the part. Water is supplied to the reservoir, to flow over the upper end of the collar and through the tube against the part. A supporting surface on the housing supports the housing on the part and depends downward from the bottom of the housing.