Is there a way to update the Inventory of a simple Product/Item?

[PreOrder_Apps]

I cannot believe I am posting this question because I own an official Square Partner company, but either I am on official brain freeze today or I'm just missing this and it's really obvious...but, is there a way to set the inventory on a simple item? Like something with no variations or options? 

Like, I have 4 of these. Period. I don't see anything like this under the Edit Items section.

Thanks!

[PreOrder_Apps]

Never mind. I just figured this out. Seems like "simple" items (ie with no variations) will have the quantity field, but otherwise they don't.