Gray cast iron pipe is a type of pipe made from gray cast iron, a material known for its strength, durability, and resistance to corrosion. 

Air valves are essential components in fluid systems that are designed to release air or gases from pipelines while maintaining the integrity of the system. 

Steel pipes are widely used in various industries and applications due to their numerous advantages and benefits.

Sizing a check valve involves determining the appropriate valve size and specifications based on the specific application requirements and system parameters.

Ductile iron pipe is commonly used in various applications, including water and wastewater systems, due to its durability and strength.