From the Sundown Website. So if you're going sealed you want 2 cf, ported will be 3.5 cf
Sealed 1.0 ft^3
Ported 1.75 ft^3
Displacement 0.12 ft^3
Depth 6 1/2"
Outside Diameter 12 1/4"
Cut-Out 11 1/8"
Recommended Tuning 32hz
Recommended Port Area 28 in^2