Phased array ultrasonic testing probes are made up of several piezoelectric crystals that transmit/receive independently at different times. An ultrasonic beam is focused using time delays, which are applied to the elements to create a constructive interference in the wavefronts. This interference allows the energy to be focused at any depth and angle in the test specimen. Each element radiates a spherical wave at a specified time, creating waves that converge and diverge to create an almost planar wavefront at the specified location. Changing the progressive time delay allows the beam to be steered electronically and swept through the test material like a searchlight. When multiple beams are put together it creates a visual image that shows a slice through the test object.