which is a flat surface on the top of flange 19 formed with an aperture 28 the underside of space 27 is formed with a bevel 29 below aperture 28 the fitment portion 11 comprises an annular flange 31 having an upward offset 32 at its inner edge merging into an annular rim 33 parallel to flange 31 extending up from the inner edge of rim 33 is spout 34 which has an upper edge 36 with a peripheral flange 35 dimensioned to fit against the shoulder 21 in the assembled position shown in fig4 the seat 22 of cap 12 fits immediately inside the upper edge of the spout 34 internal threads 37 are formed on the interior of spout 34 shaped to mesh with the threads 23 the materials of which the fitment 11 and cap 12 are molded are sufficiently flexible so that when the cap 12 is pulled down relative to the fitment 11 the threads 23 and 37 slip past each other and then interengage a seal ring 38 slants downward inward to engage the smooth surface 39 on the exterior of skirt 17 below threads 23 the primary seal of the fitment and cap is preferably the seal of surface 38 with smooth surface 39 a modification of the structure of fig3 and 4 is shown in fig3 a and 4a respectively the seal ring 38a is located spaced above the lower end of the spout 34a and this and.