The 491M/B/SD gas standards generator dynamically blends precisely known gas standards with parts-per-trillion (ppt) analyte concentrations. The system uses two stages of dilution to achieve ppt concentrations. The first stage combines the emission of analyte vapor from the company's Trace Source™ permeation tube with a precisely known flow of pure dilution gas to form a parts-per-billion concentration primary mixture. In the second stage, an aliquot of the primary mixture is further diluted. - La Marque, Texas - (409) 938-3627 - www.kin-tek.com