The ornamental design for a drinkflaskcapinsert, as shown and described.
FIG. 1 is a perspective view from above and to the left of the invention;
FIG. 2 is a perspective view from below and to the right of the invention;
FIG. 3 is a left-side elevational view of the invention;
FIG. 4 is a back-side elevational view of the invention; and,
FIG. 5 is a bottom view of the invention.
As shown at http://vimeo.com/16461385, the instant invention is an insert that fits in a cap for a sports bottle or flask. The insert projects upward from the cap and seals a chamber that is formed in the cap and downwardly closed by a metal foil. This chamber holds a flavored syrup, and the cap is intended to be mounted on the threaded neck of a bottle filled with water. Pushing the insert down pierces the metal foil and releases the syrup into the water.