Tru Spec Prefabricated enclosures are simple, straight to the point, subwoofer specific enclosures dialed in precisely to manufacturer's specifications after displacements. These subwoofer specific enclosures will be versatile to many other subwoofers as well, so you do not have to use the noted driver on the enclosure, see list below of suitable drivers that will also work well in this enclosure. 

MADE IN THE USA

TRU SPEC PREFAB SINGLE 8: Sundown SA 8" with double flush baffle

Material: 0.75" MDF 

Specifications:

Box External Dimensions
Width × Height × Depth

20.00" × 10.50" × 11.26"

Material Thickness

0.75"

Net Internal Volume

0.65 ft3

Tuning Frequency

35 Hz

Port Area

9.00 inch2

 

Cutout Diameter: 7.45"

Flush Trim Diameter: 9" 

Also fits the following 8" Subwoofers and are close to recommended specifications: