28 Spline Rear Axle 3/8-24 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. *- Fits all except 427, 428 and Boss 302.