Techna-Fit's hoses are made with Hyperline FX, a smoothbore convoluted PTFE hose. FX has extreme flexibility, great flow rates, and the ability to withstand high temperatures, a perfect fit for the Mazda Rx-7 engine. These hoses will outlast and out perform the OEM hoses 10 to 1, due to a larger I.D. (.652 inches) you will get less restriction and better flow. Made with steel metric fittings manufactured to the same sizes as the OEM fittings.