7/16-24 Fitting on Axle Lines. STOPFLEX?? incorporates a special 4 layer design for superior strength and virtually no volumetric expansion. It starts with a Teflon PTFE core (liner) which is wrapped first in a Kevlar braid, followed by an elastomer barrier and then it's strengthened further by the outer stainless steel braid. Replacing original equipment rubber hoses with STOPFLEX?? stainless steel braided hoses will increase braking performance by doing away with the soft spongy brake pedal. Rubber hoses expand, with the approximately 1200 psi. generated under hard braking. STOPFLEX?? results show a firmer pedal, allowing more control during braking.