Off-set tubing string segments for selective location of downhole tools

A system and method for selective isolation of multiple wellbore intervals that can include an isolation mandrel interconnected in a tubing string, where the isolation mandrel includes an entry bore, a transition chamber, and an exit bore, the transition chamber being positioned between the entry and exit bores, and the transition chamber being radially enlarged relative to the entry and exit bores. An isolation device, with a predetermined length, is displaced through the tubing string to the isolation mandrel, where the length of the isolation device relative to a length of the isolation mandrel can determine if the isolation device passes through the isolation mandrel or lands in the isolation mandrel.