Threaded fittings are piping components that join two pipes or other components together using threaded connections. They are made from a variety of materials, including steel, stainless steel, brass, and plastic.

The most common types of threaded fittings are:

Elbows: These fittings are used to change the direction of a pipe.
Tees: These fittings are used to create a branch in a pipe.
Couplings: These fittings are used to connect two pipes of the same size.
Unions: These fittings are used to disconnect two pipes for maintenance or repair.
Caps: These fittings are used to close off the end of a pipe.
Plugs: These fittings are used to block a hole in a pipe.
Bushings: These fittings are used to reduce the size of a pipe.
Threaded fittings are specified by their size, material, and type. The size of a threaded fitting is the nominal diameter of the pipe it is designed to connect. The material of a threaded fitting is the type of metal or plastic it is made from. The type of a threaded fitting is the specific design of the fitting, such as an elbow, tee, or coupling.

The technical specifications of threaded fittings include the following:

Pressure rating: This is the maximum pressure that the fitting can withstand.
Temperature rating: This is the maximum temperature that the fitting can withstand.
Thread type: This is the type of thread used on the fitting. The most common thread types are NPT (National Pipe Thread) and PT (Pipe Thread).
Finish: This is the surface finish of the fitting. The most common finishes are smooth and threaded.
Coating: This is a protective coating applied to the fitting. The most common coatings are zinc and epoxy.