Molded in black phenolic, the Century sports a crisp design with sharp, beveled edges and large glass window for easy viewing. Available in 3-1/2" and 4-1/2" sizes, this style can be ordered in ranges from 10 to 3000 watts. At low values of power, errors can be expected in standard wattmeters due to power dissipation. This error is corrected in Simpson's Compensated Wattmeters. Standard wattmeters have a single phase accuracy of ±2% of full scale. Compensated wattmeters have an accuracy of ±3% of full scale ( F.S.). Wattmeters have a dynamometer movement that is calibrated for either magnetic or non-magnetic panels and for a frequency range of 25-125 Hz. The dynamometer movement is air-damped utilizing the same high quality pivots and jewels as the other fine Simpson meters to support the moving element. This style of meter is ideal for many other electrical functions.