The performance characteristics, such as time delay, spurious response levels and bandwidth, of multiple‐reflection‐type delay lines are discussed. State of the art performance is indicated, and efforts to improve these characteristics are described. The time delay is determined by the path length of a given design and size limitations on the fused‐quartz blanks. Multiple symmetry designs are derived from regular polygons by rotating facets to achieve long path lengths. Typical designs are presented, and the delays that can be achieved in readily available blanks of fused quartz are indicated. Spurious responses result from diffraction at the transducer and subsequent reflecting facets, and from reflections at the transducers. “Creation angle” spurious responses characterize multiple symmetry type designs, resulting in the use of simpler designs for many critical applications. Aperturization techniques may be employed to control the size of the reflecting facets, and hence to control certain diffraction effects. The delay‐line bandwidth is a function of the transducer resonant frequency, bonding techniques and delay medium characteristics. The dependence of bandwidth on bonding parameters is discussed in terms of the transducer equivalent circuit. Medium losses increase with frequency, and limit the attainable bandwidth for long delays. The ultimate performance capabilities of multiple reflection type delay lines using materials and techniques currently available are considered. Limitations imposed on the time‐bandwidth product and dynamic range are discussed. Practical upper limits are considered in terms of figures of merit for communications and radar applications.