full flowing communication with bore 107 and valve 104 will be pivoted 90 u00b0 out of the flow passage area fig4 is a cross section view of the tubing tester in the full open position and is taken at line 4 4 of fig2 fig4 illustrates the new orientation of the housing 102 the valve seat sleeve 106 the sliding mandrel 103 and the flapper valve 104 fig5 is a close up illustration of a portion of the tubing tester shown in disassembled form in fig5 the lower end of the valve seat sleeve 106 is illustrated with the seal retainer ring 105 removed therefrom for better clarity the lower end of the valve seat sleeve 106 contains an inwardly projecting angular annular shoulder 122a formed therein this shoulder provides a portion of the tapered valve seat for receiving in sealing engagement the tapered valve surface 123 of flapper valve 104 see fig4 the lower surface of shoulder 122a forms an angle a with a plane perpendicular to the central longitudinal axis of the tubing tester the upper surface of shoulder 122a forms an angle b with the same perpendicular plane the retainer ring 155 has a notched upper end with an inner angular ridge 122b formed by said notch the inward surface of ridge 122b forms an angle c with the inner surface of ring 105 which in turn is generally parallel to the central longitudinal axis of the tool the opposite surface of ridge 122b forms an angle d with the perpendicular plane mentioned above the remaining surface of the v groove formed in top of ring 105 forms an angle e with the same perpendicular plane the angles c and d generally are complimentary angles thus insuring that.