FIG. 1 is a perspective view of a spa shell showing our new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a cross-sectional view thereof, taken in the direction of line 4-4 of FIG. 3;
FIG. 5 is a cross-sectional view thereof, taken in the direction of line 5-5 of FIG. 3;
FIG. 6 is a cross-sectional view thereof, taken in the direction of line 6-6 of FIG. 3;
FIG. 7 is a cross-sectional view thereof, taken in the direction of line 7-7 of FIG. 3;
FIG. 8 is a cross-sectional view thereof, taken in the direction of line 8-8 of FIG. 3;
FIG. 9 is a cross-sectional view thereof, taken in the direction of line 9-9 of FIG. 3;
FIG. 10 is a cross-sectional view thereof, taken in the direction of line 10-10 of FIG. 3;
FIG. 11 is a cross-sectional view thereof, taken in the direction of line 11-11 of FIG. 3;
FIG. 12 is a cross-sectional view thereof, taken in the direction of line 12-12 of FIG. 3;
FIG. 13 is a cross-sectional view thereof, taken in the direction of line 13-13 of FIG. 3;
FIG. 14 is a cross-sectional view thereof, taken in the direction of line 14-14 of FIG. 3;
FIG. 15 is a cross-sectional view thereof, taken in the direction of line 15-15 of FIG. 3;
FIG. 16 is a cross-sectional view thereof, taken in the direction of line 16-16 of FIG. 3; and,
FIG. 17 is a cross-sectional view thereof, taken in the direction of line 17-17 of FIG. 3.
The broken lines show portions of the spa shell that form no part of the claimed design.