This is for academic writing purposes.
I am trying to come up with a word that could indistinguishably describe a bottle or a can within a pack of beer. I cannot say "a unit" because "a unit" in my field means a pack (of beer). For example, when we say, price per unit of beer, it means, price per 1 pack of beer. I, on the other hand, seek to say "price per bottle/can" within such unit. Is there a word that is equally suitable to describe either a bottle or a can?