In one embodiment a print liquid supply apparatus is provided to supply liquid to a liquid needle of a receiving station comprising a liquid container including an at least partially collapsible liquid reservoir an interface structure at a side of the container, including a liquid channel that includes a reservoir connecting portion that fluidically connects to the reservoir and a needle receiving portion to allow the liquid to flow from the reservoir to the needle; a liquid interface of the liquid channel adjacent the needle receiving portion and at a distance from the reservoir connecting portion, a front wall and/or edge adjacent the liquid interface including a push area which is disposed between the liquid interface and the container; and at least one key pen base and key pen protruding from the base in a direction parallel and opposite to the needle insertion direction; and a contact pad array next to the needle receiving liquid channel portion. In another example a sub-assembly of such apparatus is provided.