Ground Zero GZUW 8SQX subwoofer 8" (200 mm).

Ground Zero GZUW 8SQX Uranium subwoofer 8" (200 mm).

These subwoofers are not made to make SPL records. These are made to give a natural and accurate sound with all the low notes. 
Listening pleasure with all kinds of music. You can use almost any type of enclosure, but for the very best results small sealed is the way to go. 
Sensitivity is good so you can invest your amp money to quality instead of thousands of watts. Excellent choice to car specific enclosures.