Stock(L) and NON stock item(N)

Team,

Good day guys.

Am not clear about the stock(L) and non stock item(N) in SAP PM. So i created a tasklist with all components in it (L )for plant A . I created and scheduled a single cycle PM plan and i found some items in the order (Components tab) are L and some are N. Not sure why ? Trying to understand the logic behind this.

Why would my tasklist show as stock item (L) for all the items, whereas the work order shows as (N) for few items & (L) for few items when i schedule the same tasklist.

Any help in understanding this logic highly appreciated.

Thanks,

N