HOW TO FIND A FILTER CARTRIDGE REPLACEMENT USING THE UNICEL REPLACEMENT GUIDE 1. Measure the outside diameter of the cartridge (in inches, +/- 1/32). 2. Measure the cartridge length (in inches, +/- 1/16) including end caps but excluding any handles or other extensions. Unicel recommends measuring through the center (if possible) rather than along the outside edge. 3. Identify the cartridge outside edge end cap configuration using the chart on the opposing page. If the top and/or bottom is open, measure the inside diameter (in inches, +/- 1/32) of the top and/or bottom. 4. Record the OEM name and model of the filter the cartridge came out of (if possible). 5. Count the number of pleats (+/- 2) and note whether there is a center core or not. The information gathered in 1-5 above can then be used to identify a proper replacement. On pages 1 to 18 of the 2010 Replacement Guide, Unicel cartridges are grouped into “series” based on the outer diameter (O.D.) of the cartridge. For example, the 2000 Series is comprised of cartridges between 2 and 2.99 inches in O.D.; the 9000 Series is comprised of cartridges with an O.D. of 9 inches or greater. Note that if the cartridge O.D. is either, for example, 4-15/16 or 6-15/16 it may be necessary to check the next series, the 5000 Series and 7000 Series, respectively. Within each series, cartridges are listed sequentially by O.D. and cartridge length and identified according to end cap i.d. and configuration, pleat count, media, and respective OEM. Unicel cartridges listed between horizontal lines are interchangeable.