Abstract: A coke oven decarborizing air regulating assembly comprising a manifold pipe extending along each side of a battery of coke ovens for feeding gas to a plurality of separate pipes leading to burners in the ovens, each of which pipes includes an air regulating assembly comprising a cylindrical pipe section with a plurality of holes cooperating with the edge of a relatively slidable cylindrical sleeve having an end plate or "cookie" with a handle for slidably moving the sleeve longitudinally to quickly regulate the amount of air introduced into the oven. The handle also serves as a stop element to prevent abnormal insertion of the sleeve into the pipe -- also it may predetermine the normal opening of the air admitting holes.