Diamond Series Subwoofers offers incredible quality and precision engineering for this class of subwoofer. 

SPECIAL NOTE:   LIKE ALL DUAL VOICE COIL SUBWOOFERS A DUAL 2 OHM SUBWOOFER IS ACTUALLY A 1 OHM...OR 4 OHM SUBWOOFER -
IT WILL NEVER BE JUST 2 OHMS!!   
AND A DUAL 4 OHM SUBWOOFER IS ACTUALLY A 2 OHM...OR 8 OHM SUBWOOFER -
IT WILL NEVER BE JUST 4 OHMS!!

BE CAREFUL WHEN DESIGNING YOUR AUDIO SYSTEM AND YOUR SELECTION OF AMPLIFIER/SUBWOOFER COMBINATION(S).   LOWER IMPEDANCE IS NOT A GOOD THING.  DAMPENING FACTOR OF THE AMPLIFIER SUFFERS (HOW IT CONTROLS THE SUBWOOFER) AND THE HEAT OF ANY AMPLIFIER DOUBLES WITH EVERY HALVING OF IMPEDANCE.  NOT A GOOD THING!!!  REMEMBER THAT HEAT IS YOUR ENEMY.