HDS (Heavy Duty Street) series is perfect for SQL systems. They'll
deliver block rattling bass on 600-1200 watts RMS. They're available
with a 2.5" or 3" coil depending on what best fits your application. The
HDS subs will make sure they hear you before they see you!
HDC (Heavy Duty Competition) are exactly as the name states! Everything
about the HDC is bigger and badder than anything that even comes close
to the same price on the market. We recommend having 1500-2000 watts RMS
minimum to realize the true potential of the HDC sub-woofers.The HDC
motors are bigger, the cones are stiffer, they have 10 gauge direct
connect leads, and we use the best 3" and 4" high temperature voice
coils available. They'll still perform well in high power daily applications, but we truly designed these to take a beating in competition.