Container with frangible device interface

A cap for a bottle which includes a frangible device interface comprising a valve part, wherein the bottle contains a liquid or gel product and has a neck upon which is mounted the cap, the cap comprising an interior cavity defined by an annular sidewall, a valve plate, and a cap face, wherein the valve plate further includes a liquid outlet leading from the interior of the bottle into the interior cavity the liquid outlet having an annular wall surrounding a central bore, an outlet valve element, and further depending from the valve plate is a tethered pull-ring which is recessed within the interior cavity, wherein the cap further includes a channel intermediate the annular sidewall and the valve plate and which defines a frangible region of reduced thickness in the material forming the cap.