Dial of a large-sized clock is made of steel except for internal illumination type which is made of acrylic resin. Input signal of a wall type secondary clock is 30 sec. polarized signal/DC 3.6 V.rCost for installation work is not included. Power consumption of ø550-and ø700-mm types is 20 mA, and that of ø900-and ø1,000-mm types is 60 mA.