How to describe a single item within supplies?

I’m trying to translate terms used in a database to terms used by end-users. There is a supplies table which holds information on supplies held in stock. Supplies is generic on purpose, as there is no one specific category or type. Each record details a single item/thing held and what it is, how much is in stock, etc.

I refer to supplies as ‘supplies’ for the end-user, but I’m struggling with the singular form.

• I’ve tried ‘supply’ but it doesn’t seem to fit, e.g. "add a supply" and "edit a supply" doesn’t sound right.
• The word ‘item’ doesn’t mean much without context and using that in actions also feels awkward, e.g. "add an item" – an item of what, add to where?

Should I stick with ‘supply’, or is there a better term?