Abstract: A blade holder and nozzle assembly connectable to a flexible container closure element such that when the blade holder and nozzle assembly is connected to the flexible closure a circular opening is formed in the flexible closure and surfaces on the blade holder and nozzle assembly and on the flexible closure are urged into sealing relation. The assembly comprises a hollow, tubular body having a shoulder extending around the interior thereof dividing the interior of the body into a threaded bore in the lower end of the body and a nozzle in the upper end of the body. A single cutting blade having a pointed end and a single cutting edge is secured to the shoulder and extends into the threaded bore such that as the body is threadedly secured to a flexible closure element, the cutting blade pierces the upper surface of the closure element and as the body is rotated the blade cuts a circular opening in the upper end of the closure element.