Rising Dragon Plastics is the largest manufacturer in China of Hot Tub jets, they can be found on countless brands of Chinese spas & Hot Tubs here in the UK. Rising Dragon Jets can also be found on a few American Spa brands such as Arctic Spas. In the early years of their manufacture of Spa jets, the rear diffusers were a clip-in style which is now replaced with a modern superior thread-in version called Quantum Jets. If you have an old clip-in style Rising Dragon jet it can be replaced with a thread-in jet, to do this you need to swap the jet retaining ring located in the jet body.