Tara Labs Temporal Continuum loudspeaker cables. These are very rare in the fact that they can optimize the amp & loudspeaker combo by controlling the electrical damping of the amp. They are in good shape although the controller unit has yellowed with age. They have spades on both the amp & speaker ends and the pictures make them look more beat up than they do in person.
Tara Labs is a respected hi-end cable manufacturer that was established in 1984 by company founder Matthew Bond who was trained in physics and electronics theory. He was looking for ways to improve the performance of audio components and the wire used within an audio system. Matthew Bond had experimented with solid core conductors of different diameters. He hypothesized that an 'optimum diameter' of 18 AWG (American Wire Gage) or 1 millimeter was ideal for audio frequencies because there was minimal high-frequency attenuation caused by the principles known as the Skin Effect. Matthew Bond's work was corroborated by research work from the NBS or National Bureau of Standards in the 1930s and confirmed later by Stereophile in July 1988, in a table presented as the DC to AC resistance ratio versus frequency in wires of different diameters. Matthew Bond is credited with the invention of solid-core wires for audio use because his work predates Dennis Morecroft (1984) and any of the early solid-core wires developed for use in audio in England at the time.
TARA Labs introduced Rectangular Solid Core cables. These cables employed solid core conductors with a rectangular cross-section and can be made in specific proportions(width and height). This affects the tuning of the frequency response of a conductor as compared to around a conductor of the same size or DC resistance.