Vented subwoofer enclosure 12” features;
Single 12-Inch one-breather Sub woofer Box; Car Audio Stereo Bass Speaker Sub Enclosure.
They are designed to fit one 12-inch subwoofer.
Dimensions: Length 50″ width 39″ height 34″
With a single breather
Vented subwoofer enclosure 12” is made of Chipboard material, making it stronger and more durable.
Here are more options on Automotives.