to close these ports it is important to recognize that in fact the closing sleeve 60 is staying in position and the rest of the tool is moving uphole the relative displacement of the items being identical before the full intended stroke in the uphole direction of the balance of the tool the downhole end of the closing sleeve 60 comes in contact with piston stop 56 see fig4 b and loads shear screw 58 at a selected load the shear screw 58 will shear allowing piston stop to move see fig5 b relative to the tool along with closing sleeve 60 such that as the tool moves uphole closing sleeve 60 and piston stop 56 are stationary the relative downhole movement of closing sleeve 60 relative to opening sleeve 50 allows seal 54 to come in sealing engagement with closing sleeve 60 thus sealing closed ports 52 following piston stop 56 and closing sleeve 60 reaching a final position the movement of the ported mandrel 14 will have been sufficient to locate recess 34 directly radially inwardly of collet fig3 allowing the collet fingers to snap back into an unactuated condition and to engage back angle 32 with the ported mandrel 14 note distinction fig4 b and 5b this locked position enables two things the first being that the closing sleeve 60 is locked closed and cannot be accidentally opened and secondly that because the outside dimension.