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