The following description was prepared by William Gross:
Breastplates – ornamental metal plates or shields hung in front of the Torah scroll – are found in all Ashkenazi communities, as well as Italy and Turkey, but designed differently in each community. In most cases the breastplate is made of silver or silver-plated metal. In Italy the breastplate is shaped like a half-coronet and known as the Chatzi-keter, "half-crown." In Turkey, the breastplate is called a Tas, and assumes a variety of shapes – circular, triangular, oval, or even the Star of David. In Western, Central, and Eastern Europe the breastplate is called either Tas or Tziz; its function there is not merely ornamental: it designates which Torah scroll is to be used for the Torah reading on any particular occasion, with interchangeable plaques.
The most notable early breastplates, from 17th-century Germany and Holland, were either square or rectangular, but over time they became rounded and decorative, and bells or small dedicatory plaques were suspended from its lower edge. During this period, the design of breastplates was influenced by that of the Torah Ark and the parokhet (curtain) concealing it, featuring various architectural motifs, the menorah (the seven-branched candelabrum), Moses and Aaron, lions, or Torah crowns.
This 4Tas from the Slovakian town of Kosice is a companion piece to the Yad by the same maker, which is found in the Gross Family Collection, 052.001.001. He was a well-known silversmith and the quality of the workmanship on this object attests to his skill. An unusual feature of this Torah Shield is a portion indicator using an inscribed round disc with a display area cutout over it to indicate the particular portion to be read. This is in place of the plaques that are normally found.
Inscription: K(eter) T(orah) {Crown of the Torah)