FIG. 1 is a side perspective view of a flotation device with back support;

FIG. 2 is a top view of the flotation device with back support illustrated in FIG. 1;

FIG. 3 is a rear view of the flotation device with back support illustrated in FIG. 1; and,

FIG. 4 is a right side view of the flotation device with back support illustrated in FIG. 1, the left side view being a mirror image of the right side view.

The broken-jagged lines which define the boundary of the claimed design do not form part of the claimed design. The broken lines are for environmental purposes only and form no part of the claimed design. The broken-alternating thick and thin lines illustrate a cross-section of the design and form no part of the claimed design. In addition, the bottom of the flotation device not shown forms no part of the claimed design.