this is an improvement in wellstein &# 39 ; s u . s . pat . no . 3 , 812 , 910 issued may 28 , 1974 comprising generally : an improved shaped frustoconical seat for the saddle contoured gasket or seat in the washer or nut for better sealing the outside of the well casing with the outside of the nipple that extends through the hole therein for withstanding higher pressures ; and / or the employment of a pair of gaskets inside and outside the casing surrounding the nipple and contoured to the interior and exterior walls of the casing , also for insuring better sealing . the nipple portion of the hanger member has its outer end externally threaded for a nut member which may contain an internal angular frustoconical groove or seat for a saddle contoured gasket which presses the gasket both against the outside cylindrical surface of the nipple outside the outer wall of the casing and against the outer wall of the casing , or the nut may press against a washer which contains such a groove or seat , and may also include a second gasket between the nut and the washer .