Seiko is perhaps best known for its wristwatches, all of which were at one time produced entirely in house. This includes not only major items such as microgears, motors, hands, crystal oscillators, batteries, sensors, and LCDs, but also minor items such as the oils used in lubricating the watches and the luminous compounds used on the hands and the dials. Seiko watches were originally produced by two different subsidiaries. One was Daini Seikosha Co.,(now known as Seiko Instruments Inc.), and the other was Suwa Seikosha Co.(now known as Seiko Epson Corporation). Having two companies both producing the same brand of watch enabled Seiko to improve technology through competition and hedge risk. It also reduced risk of production problems, since one company can increase production in the case of decreased production in the other parties.