The ornamental design for a flask with cap, as shown and described.
FIG. 1 is a perspective view taken from the top, front, and left side of the flask with cap showing our new design.
FIG. 2 is a front elevation view of the flask with cap of FIG. 1.
FIG. 3 is a right side elevation view of the flask with cap of FIG. 1, the opposite side being a mirror image thereof.
FIG. 4 is a top plan view of the flask with cap of FIG. 1; and,
FIG. 5 is a bottom plan view of the flask with cap of FIG. 1.
The broken lines in FIGS. 1, 3 & 5 are included for the purpose of illustrating the portions of the flask with cap that form no part of the claimed design.
The unshaded areas immediately adjacent the broken lines likewise form no part of the claim.