Flexible container with neck portion

A flexible container 10 for storing fluid includes; a body 12, a neck portion 20 formed of at least one flexible sheet 22, said neck portion defines a discharge passage between the hollow interior of said body, and an opening 30 which may have a frangible end portion 28. The neck portion having a width in a range of 0.25-0.50in (0.635cm - 1.27cm) when the sides of the flexible sheet are flat against one another, a length in a range 0.37-0.62in (0.94cm -1.57 cm) when open, and an effective cross sectional area in a range of 0.010-0.018 in2 (0.065- 0.116cm2). Fluid having the viscosity and density of water will not flow from the hollow interior of said body when said body is subjected to applied pressure less than 0.1 psi (0.0070kg/cm2) as said container is tilted from the vertical, until said container is angled at least 70 degrees from vertical. Such fluid will smoothly discharge from the hollow interior of said body if said body is subjected to applied pressure of 0.1-0.25 psi (0.007-0.0176 kg/cm2). The neck portion may be integral with or secured to the main body.