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PURCHASED BY S&S No. 1HV. The U.S. Environmental Protection Agency has renewed their contract for these ultra-pure glass fiber filters for high- volume air sampling. It's official. We will continue to supply EPA with our No. 1HV filters for use in the National Air Surveillance Network. This is the second year in a row they've selected our filter. It makes sense. We designed and developed No. 1HV for that purpose. We made it tough enough to satisfy the strict requirements that EPA set for high volume air sampling. It combines exceptional purity with consistency, and uniformity in size, weight and strength. Pure borosilicate glass microfibers per- mit chemical analysis of trace pollutants with a minimum of interference or background. Every No. 1HV filter is serially pre-numbered for positive sample identification, and can be folded easily without crack- ing. Sheets are 8" χ 10" and packaged 50 to a box. For a descriptive brochure and two sample sheets, write to us on your letterhead. Schleicher & Schuell, Inc., 543 Washington Street, Keene, N.H. 03431. Phone (603) 352-3810. Schleicher& Schuell Schleicher & Schuell, Inc. Keene, New Hampshire 03431 Schleicher & Schüll GmbH, D-3354, Dassel, West Germany Schleicher & Schüll AG, 8714, Feldbach ZH, Switzerland CIRCLE 189 ON READER SERVICE CARD ANALYTICAL CHEMISTRY, VOL. 51, NO. 11, SEPTEMBER 1979 • 1033 A THE EPA. AGAIN.
