The ornamental design for a mitten with an opening at distal end, as shown and described.
FIG. 1 is a perspective view of a mitten with an opening at distal end, according to my new design.
FIG. 2 is a front elevation view thereof;
FIG. 3 is a back elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The partial human hand shown in broken lines is environmental subject matter included to illustrate how the design may appear when worn and forms no part of the claimed design. The cuff portion shown in broken lines and the single broken line surrounding the thumb opening represent features of the article of manufacture that form no part of the claimed design.