The ornamental design for a reloadkit for fireextinguisher, as shown and described.
FIG. 1 is a side plan view.
FIG. 2 is a rear plan view.
FIG. 3 a bottom plan view; and,
FIG. 4 is a top perspective view.
Broken lines in the drawings are included for the purpose of illustrating an environment and form no part of the claimed design. The claimed invention can be used in other environments.