Description Fabrimetricsâ traditional premium quality irrigation dam material uses only 100% virgin resins in both the high-density yarn and the low-density coating with maximum color pigmentation and UV inhibitors. Our factories use a wider loom, so the dams are made without a heat seal through the 9â depth. The blue material features a 6" loop (or sleeve), sewn with 100% polyester thread using a double-needle chain stitch with 4 to 5 stitches per inch.