Ultrasonic spectroscopy has for a long time been thought promising for characterization of thin layers immersed in water or embedded between two known materials (similar or dissimilar) [1]. Significant effort has been put forth by many authors [2]–[14]. An ultrasonic spectroscopy method for determination of the complete set of acoustical and geometrical properties of an isotropic layer embedded between two known materials (similar or dissimilar) has been developed recently in [15]. The uniqueness of the method is its ability to determine all the layer properties - thickness, density, elastic moduli and attenuation (longitudinal and shear) - at two incident angles: one normal and one oblique.