Systems for landing wire line tools at selected levels within a well tubing string

For use in a system in which wire line tools are adapted to be landed at selected levels within a well tubing string, an assembly comprising first and second wire line tools both having seals thereabout of equal diameter and latches for latching the tool in landed position within said string, said first tool having a shoulder above and of larger diameter than its seal, said second tool having a shoulder below and of lesser diameter than its seal, a nipple connectible as part of a well tubing string and having a bore therethrough in which either of said first and second tools may be landed, said bore having a polished section with which the seal about whichever tool is landed therein is sealably engageable, a first seat in the bore above and of larger diameter than the polished section to land said first tool when the shoulder thereof is lowered into engagement therewith, a groove in the bore beneath the polished section, a ring releasably disposable within the groove to provide a second seat of smaller diameter than said polished section to land said second tool when the shoulder thereof is lowered into engagement therewith, and a recess in the bore to receive a latch on whichever tool which is landed therein.