Fine Accuracy) or ‘Special’ on the dial. Many of these were of the "Vantac" sub-line and featured colorful dial faces and faceted crystals. Other Seiko produces electronic devices as well; during the 1980s, the company produced a notable range of digital synthesizers, such as the DS-202 and DS-250, for use in electronic music. Today the music division (part of Seiko Life Sports) produces metronomes and tuning devices. Movements Mechanical movement In 1968, Seiko introduced three ten beat (ten ticks per second) calibers, the automatic caliber 61GS, the manual winding 45GS and 19GS for women's watch. The 61GS was Japan's first automatic ten beat watch, and it was the most accurate mechanical watch due to the high beat calibers. The calibers are considered high beat because normal mechanical movements beat six to eight times per second, and higher beat makes the watch more resistant to shock, thus achieving the high accuracy. In 2009, Seiko released the new ten beat caliber 9S85, which is a completely new design from the previous high beat caliber. The new caliber also met the Grand Seiko Standard, a chronometer certification that the company claims to be more strict than the Chronometer Certificate in Switzerland. List of Seiko mechanical movements Quartz movement On December 25, 1969, Seiko released the world's first quartz watch, the Seiko Quartz ASTRON, marking the beginning of the quartz revolution. The watch used a crystal oscillator for accuracy, where the crystal generates steady vibration when voltage is applied to it. During the ten years of development at Suwa Seikosha, Seiko managed to create many parts which enabled the viable application of quartz in wristwatches. For example, Seiko cut the crystal oscillator into the shape of a tuning-fork, and developed an integrated circuit and step motor to operate with the signals from the crystal oscillator. Although creating the parts that enabled quartz watches, Seiko did not monopolize the patent rights for the unique pieces, but decided to open them. In 1973, Seiko announced the world's first LCD quartz watch with six-digit digital display. In 1975, Seiko launched the world's first multi-function digital watch, the 0634. In 1978, Seiko released the Twin Quartz watch to address the effect t of temperature on the frequency of the quartz crystal oscillator, which put a limitation on the accuracy of quartz watches. Seiko put a second crystal in the watch that is linked with a processor that detects