Creating Where-Used Lists for PRTs 
Use
Using where-used lists, you can display in which maintenance task lists specific production resources/tools (PRTs) are used. From this list of task lists, you can access the header data for the individual task lists and the detailed data screens of the individual operations.
You can use where-used lists for all four categories of
PRT types.Procedure
The screen PRT Usage in PM Routings: Selection is displayed.
In the pop-up window PRT category, select the desired PRT category and choose Select.
You see a pop-up window in which you can select the overview version you require. For more information, see
Pre-Setting Overview Variants.The system displays a list of all the elements corresponding to the object overview version and your selection criteria. This means that all the elements displayed contain the specified production resources/tools.