embodiment of fig1 there are two collet grooves however it will be understood by one of ordinary skill in the art that one or more of those grooves could be machined into nipple 10 the width and configuration of those grooves may be whatever is desirable to serve the purpose in a stack system where more than one nipple is connected into the tubing string it may be desirable to have the nipples be selective with respect to the locating device to be run thereafter in one embodiment the largest collet groove width may be on the deepest nipple within the well such that a locating device being run will skip earlier collet grooves and engage the smallest groove in which the collet can fit alternate embodiments are also contemplated for example the particular collet groove profile can allow a smaller collet to bridge over certain features such as raised portions in a larger total collet groove size still referring to fig1 the nipple further includes an orientation slot which is a recess of any desired configuration for engagement with an orientation key existing on the locating device discussed below the orientation slot provides for the angular orientation of the locating device within the wellbore more specifically.