A clock face is centered on all four sides of the tower from the 25th through 27th floors. Each clock face is in diameter, while the numerals on the clock faces are four feet (1.2 m) tall. The numerals and minute markers on the clock faces are edged with copper, while the minute and hour hands are made of iron with a copper sheathing. The minute hands weigh and are long, while the hour hands weigh and are long. The mechanism was controlled by electricity, a novelty upon the tower's completion. The master clock, which controlled the large clock faces as well as a hundred other clocks in the same complex, was located on the first floor of the former home office, and ran with a maximum error of five seconds per month.