Check the listing for details. MOON AMERICAN 664-252 Hydrant Cap,Female,Plastic,NH 6APH2. Condition: New. Listed at 14.76 USD. Hydrant Cap, Compatible Pipe Size 2 1/2 in, Hose Fitting Gender Female, Includes Chain Yes, Thread Type NH, Tightening Method Rocker Lug, Material Plastic, Breakable No, Color Red, Includes Chain, Gasket, Thread Size 2 1/2 Plastic fire hose and hydrant caps are nonconductive, lightweight fittings that resist corrosion and rust. They are more economical than aluminum or brass fire hose and hydrant caps, making them a common choice. They twist onto fire hydrant and hose openings to keep out dirt and prevent damage to external threads. Some plastic caps are breakable to save time in an emergency.Fire hose and hydrant caps and plugs are accessories that protect the open ends of hydrants and hoses when not in use. Caps cover fire hydrant and hose openings to keep out dirt and prevent damage to.