SPECIAL ORDER ITEM. Review Returns Policy before purchase. This coupling with an HNBR sealing element is the first press fitting system for carbon steel pipe approved for use in gas and fuel oil applications. The is ideal for industrial, commercial, and residential applications and performs well in both new installations and retrofit projects. Tested to the strictest standards in North America, the joins carbon steel pipe reliably through the engineered design of the fittings and a battery-powered press tool.