Targum zu Schemot 38:8

And he made the brasen Laver, and its foundation of brass, from the brasen mirrors of the pious women, who, at the season, came to pray at the door of the tabernacle of appointment, standing with their oblations, giving thanks and confession, and returning to their husbands, the mothers of righteous children, who had been purified from the uncleanness of their blood.

And he made the laver of brass, and the base thereof of brass, with, the mirrors of the pious women who were devout at the gate of the tabernacle of appointment.