Inner threaded copper pipes, also known as non-smooth pipes, refer to TP2 copper pipes with smooth external surface, a certain number of internal surface and regular threads.

The thermal conductivity of the inner threaded copper tube is 20 to 30 percent higher than that of the smooth tube due to the increase of its surface area. With the energy shortage in the world and the implementation of the energy efficiency ratio air conditioning access system in China, internal threaded copper tubes will be widely used in the air conditioning and refrigeration industry.