Abstract: The present invention relates to apparatus for temporary attachment to the top of a conduit string disposed in a well bore whereby an uncontrolled fluid blowout through the conduit string can be shutoff and controlled utilizing the apparatus. The apparatus includes a housing having a central bore disposed therethrough and a side connection formed therein communicating with the bore. A vent is sealingly attached to the top of the housing over the bore and shutoff valve means are disposed in the vent. A tubular member, the upper end of which is rotatably and sealingly disposed within the bore of the housing projects below the bottom of the housing and means are formed on the lower end of the tubular member for sealingly gripping the inside surfaces of the top of the conduit string upon the rotation of the tubular member.