[Koha] Clear as Mud to a non-librarian tech guy

We've upgraded to 3.14 and the librarians have pointed out to me that whenever they are checking out an item, that there is a statement that the item is not renewable. I've spent the better part of my day trying to find out where to change this. The Items type look promising but when I clicked to edit it, there was not renewable option. Anyone have a clue? Thanks, Phillip Tech Guy and not a librarian (smile).