FIG. 1 is a perspective view of a spa shell showing our new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is another perspective view thereof;
FIG. 4 is another perspective view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a cross-sectional view thereof, taken in the direction of line 6-6 of FIG. 5;
FIG. 7 is a cross-sectional view thereof, taken in the direction of line 7-7 of FIG. 5;
FIG. 8 is a cross-sectional view thereof, taken in the direction of line 8-8 of FIG. 5;
FIG. 9 is a cross-sectional view thereof, taken in the direction of line 9-9 of FIG. 5;
FIG. 10 is a cross-sectional view thereof, taken in the direction of line 10-10 of FIG. 5; and,
FIG. 11 is a cross-sectional view thereof, taken in the direction of line 11-11 of FIG. 5.
The broken lines show portions of the spa shell that form no part of the claimed design.