These injector O rings are the best injector O rings available for all performance applications. Injector O rings in racefuel, E-85 and Methanol applications should be changed EVERY season. Failure to do this can cause fuel and vacuum leaks and pose potential fire hazards. Constructed of advanced materials these O rings are less likely to fail under high manifold pressure and High fuel pressures. Team MMR has tested/used these O rings without a single failure in Methanol applications over the last 4 years! QTY 16 O rings included (enough for 8 injectors) Fits all Precision, Bosch, Siemens, ID, FAST, HOLLEY and Accell Injectors