These were perfect to cancel out some unwanted frequencies going to my alpine and Rockford Fosgate speakers. Now there is less chance of them getting damaged when I crank my tunes.

I bought these to cut some bass out of the cheap 6x9s i accuqired from a friend, they worked great and cut out the distortion from the speakers. Its been six months now still going strong!

I purchased this product in the process of creating a overall good sounding system. I have two 15 Kicker CVX subs powered by a Hifonics 1700, so needless to say I had plenty of bass, the speakers I had were getting distorted when loud. I picked up 2 pairs of these and it was a world of difference. Great overall product.

Blocked the base to my tweaters in my 2002 Mustang with factory Mach speakers.