The Pro 100 and Pro 200 Series of multi-wavelength IR temperature sensors from Williamson Corp., Concord, MA, use ESP algorithms to provide aim-and-read capabilities for non-greybody materials that are not accurately measured by single- or dual-wavelength sensors because their change in emissivity varies by wavelength. The sensors measure the amount of IR energy emitted by an object's surface, then convert the signal into a temperature value between 95°C and 2500°C. Accuracy is within 2°C or 0.25% of reading, whichever is greater. Pro 100 sensors use visual or integrated-laser aiming alignment while the Pro 200 sensors use fiber-optic alignment. Each can be used as a stand-alone transmitter with a choice of inputs, outputs, and alarms.