Available from Spectrum Detector Inc., the brochure “Analog Detector Instruments for Radiometry” describes the company’s SPI pyroelectric, SSI silicon and SGI germanium series detectors, which are offered in a variety of sizes. The four-page document notes that each of the modular, calibrated, multisensor instruments is packaged in shielded metal housing that is composed of three parts: an interchangeable detector module, a compact power supply and a versatile optical front end. The optical front end and the power supply can be used with any of the detector modules. Features, applications and accessories are listed. Performance curves and a diagram showing mechanical details are provided.