Improved performance and reliability of magnetostrictive delay lines have resulted in their increasing military and commercial use in aircraft navigation, radar, data processing, and automation. This trend has been particularly evident in the small digital computer where the advantages of this type of pulse storage, namely, economy, temperature stability, high operating speed, and expandable capacity, have enabled magnetostrictive delay lines to displace magnetic drums and cores. This paper presents the characteristics and design features of commercial delay lines. Particular attention will be paid to the following areas: 1. Transducer design. 2. Choice of delay-line materials for transducer operation and as propagation media. 3. Materials and techniques for mechanical terminations. 4. Heat treatment of wire to obtain low temperature coefficients of delay. Because of the rapid growth in the use of magnetostrictive delay lines, there has been insufficient time for industry to agree on standard definitions and measurement procedures for such delay-line parameters as resolution, signal-to-noise ratio, input impedance, terminating impedance, and attenuation figure. A presentation will be made of logical concepts on which such standardization might be based.