Abstract: A microcircuit flat package which remains hermetically sealed even under conditions of high stress. The package comprises an integral rectangular metal tubular shell having an opening in one of the broad walls, and elongated integral insulators sealed in the open ends of the tube, each insulator having an array of leads extending in sealed manner therethrough. A microcircuit is installed within the package and connected via wire bonds to the inner ends of the leads and after which a cover can be bonded onto the flat coplanar surfaces of the tubular shell surrounding the package opening to hermetically enclose the microcircuit.