The Kiyor is one of the keilim (vessels) found in the Azarah (courtyard). It is used every morning by the Kohanim (Priests) in order to sanctify their hands and feet in order to perform the avodah (service). The Kiyor only has two specifications in the Torah: that it be made of copper and that it have a base. Therefore the design of the Kiyor in the Mishkan (Tabernacle) and Bayit Rishon (First Temple) differs from the one in Bayit Sheni (Second Temple). The original Kiyor was small and only had two faucets, however the one in Bayit Sheni had twelve faucets. The reason for the additional ten faucets is because the most Kohanim needed to perform the Avodah at one time is twelve, therefore the additional faucets made the system more efficient.