Detailed Product Description Item Description Code of Filter BagCollar Ring S -- Carbon steel snap ring, zinc platedA -- Stainless steel snap ringP -- Sentinel Rings (sewing)W -- Sentinel Rings (welding)R -- Tie-on bag (no ring)M -- Modified/special ringMicron rating -- 1 to 1200 (µm)Bag material PE - Polyester needlefelt, no scrim, singedPO - Polypropylene needlefelt, no scrim, singedNY - Nylon ...