Ahlstrom 6090-1500 Qualitative Filter Paper, 15 Cm Diameter, 4 Micron, Medium Product Details Ahlstrom's qualitative grades of filter paper are, by definition, recommended for use in analytical methods, which determine or identify particulate constituents of a mixture irrespective of the amount present. Ahlstrom offers a complete range of low ash filter papers for general laboratory work that provides you with the correct combination of particle retention, filtration speed, loading capacity and wet-strength. Qualitative analysis, low ash content 0.06 percent, untreated, consistent performance, wet-strengthened grades, custom cut. These grades contain a high level of alpha-cellulose that provides high purity but will weaken when wet. The inherent strength of standard (untreated) grades does not pose a problem when they are used in routine quadrant folded applications. We do not recommend these grades for use in vacuum work or when wet handling is required. Qualitative filter papers are often used in routine separation work that still requires high purity and consistent performance Qualitative grades consist of greater than 95 percent super refined a-cellulose and linter fibers Standard qualitative filter papers are suitable for quadrant folded or gravity flow applications This grade is an evolution of ahlstrom 613 for use in the beer industry This is a filter paper with an extremely low iron and nitrogen content for the analysis of protein in beer Payment We accept PayPal and credit cards via PayPal. Taxes - US We collect sales tax, as required by law. Shipping We make every effort of shipping within 3 business day of payment clearing. The estimated delivery time is 2 - 5 business days from the shipping date. Policies If you do need to return your item, please contact us via email (you will receive an email when your product ships with additional details - Subject: Important information about your purchase). You will then be provided with a return shipping label and packing slip. Pack the item carefully. Include the packing slip, apply the shipping label, and return the item within 30 business days of the date you request a return, or your return will be canceled. Once we receive your order we will inspect the return. Please allow up to 5 business days of receiving the returned item for your refund.