The Preppy manifold is our simplest and most economical manifold. It too enables the analyst to simultaneously prepare up to 12 samples. It consists of a chemical-resistant cover and gasket, a glass basin, a vacuum release vent, 12 individual control valves with knurled tops, and stainless steel solvent guide needles. Two optional collection racks are available; one holds both 2 and 4 mL autosampler vials, and the other holds 15 and 20 mL vials. An optional vacuum gauge/bleed valve assembly can be installed to allow precise control of the vacuum used with the Preppy manifold.. 12-Port. 15 and 20 mL vials. Sold in each. . . Sigma-Aldrich 57160-U Preppy 12-Port Vacuum Manifold. Country of Origin : United States. Part Number : 1198W66EA. Pack of : 1.