SMDSMD Output Meter (SMD-OM-1)
If you are into high end car audio then you should install a SMD Output meter to monitor your system.  Droppin Hz has been my #1 internet Car Audio for all my Car Audio needs.  They have amplifiers, subwoofers, speakers,wire, you name it they have it or can get it for you.  No cheap brands here just pure SQL and SPL Audio.  Check them out Droppin Hz!!!!!