locking keys 112 so that lower pickup sleeve 49 and upper pickup sleeve 56 are free to move until surfaces 57 and 58 make contact although in frac module 146 b surfaces 57 and 58 will not make contact at this time because the operator has put set down weight on the u201c completion string u201d and also because internal pressure 22 will not pump the tool open or faces 57 and 58 apart because seals 50 51 72 and 73 on release sleeve 55 balance the effects of internal pressure 22 as pressure 22 continues to act on piston 106 piston 106 continues to move upward until expanding lock dogs 107 engage groove 108 and so piston 106 is now locked to lower pickup sleeve 49 and they will move together simultaneously lock dog 109 engages groove 110 located in release sleeve 55 the shoulder 166 of lock dog 109 does not push on shoulder 165 of groove 110 of the release sleeve 55 at this time because shoulder 168 of lock dog 107 contacts shoulder 165 of groove 108 of the lower pickup sleeve 49 in this frac module the length of shift piston 106 does not allow pressure 22 to pass seals 104 and 105 therefore the packer in frac module does not begin to set until workstring pickup occurs that allows pressure 22 to pass the seals 104 or 105 to get pressure to.