"And you shall make a laver of copper, and its pedestal of copper... " (Ex. 30:18)
The laver, a large vessel which appears like a kettle, is actually the first vessel which the priests have contact with every day, for they must sanctify their hands and feet from its waters before commencing any sacred task in the Holy Temple.
The original laver which was constructed for the desert tabernacle in Moses' time included 2 spigots for releasing the water. In the era of the Second Temple, the High Priest Ben Katin, who fashioned the muchni, also fashioned 12 faucets for the laver, so that the entire shift who participate in the offering of the daily sacrifice may sanctify themselves at once.