Grooved Fittings—National Fittings are red-painted and made of durable, high-strength ductile iron conforming to ASTMA-536. The National Grooved piping system is reliable and faster to install than welding, threading, or flanging, resulting in the lowest installed cost. It can be adapted to suit standard pipes with cut grooves or standard and light wall pipes with rolled grooves.

• All fittings are full-flow design.
• Pressure ratings of Standard fittings conform to Style 11 Couplings.
• They are made of durable, high-strength Ductile Iron conforming to ASTM A536.
• Every lot is metallurgically examined for compliance.