Grade A Fine porosity, fast flow rate, with a 1.6µm size particle retention. Frequently used in the filtration of precipitated proteins and cells. Ideally suited for use as a filter for radioimmuno assay of weak beta emitters by scintillation counting and gravimetric determination of airborne particulate. Glass microfiber filters are produced from 100% borosilicate glass microfiber without the use of binders or strengthening agents. Depth filtration categorizes filter media that traps particulate within the random matrix of fibers found within the thickness of the media. The efficiency rating of the filter is characteristic of the complex void space structure that develops as the fibers overlap. The fibers used to manufacture these depth filters are smooth and uniform. This permits their characteristically high flow rates while allowing retention of exceptionally small particles and high load capacity.