21.000 in. By 22.000 in. By 18.000 in. O/a dim., 95 to 145v, 57.5 to 62.5 hz expanded scale, 1/2 hz freq response, 2 milliseconds spike/dip voltage response, 1v/1 div sensitivity, 0.1 hz/1 div sensitivity, 50 mm chart width/channel, better than 1 pct linearity, continuously monitors and records the magnitude of the three phases of voltage and freq on 32 day chart rolls by direct writing with an inkless recording stylus for each channel
