I claim the ornamental design for a non-slip USB holder, as shown and described.
FIG. 1 is a front perspective view of a non-slip USB holder showing my new design;
FIG. 2 is a back-perspective view of the non-slip USB holder as shown in FIG. 1;
FIG. 3 is a front-side view of the non-slip USB holder as shown in FIG. 1;
FIG. 4 is a back-side view of the non-slip USB holder as shown in FIG. 1;
FIG. 5 is a top-side view of the non-slip USB holder as shown in FIG. 1;
FIG. 6 is a bottom-side view of the non-slip USB holder as shown in FIG. 1;
FIG. 7 is a left-side view of the non-slip USB holder as shown in FIG. 1;
FIG. 8 is a right-side view of the non-slip USB holder as shown in FIG. 1; and,
FIG. 9 is a perspective view of the non-slip USB holder as shown in FIG. 1.
The Dotted lines are only for environmental purposes and form no part of the claimed design. No particular colour scheme forms part of the claimed design.