Works great! By Benjamin on 4/21/2015Benjamin would recommend this product to a friendWas easy to cut to fit under my return pump in the sump. The pump wasn't loud to being with, but this did reduce some vibration which did make some noise. I imagine if your pump vibrates a lot and creates a lot of noise, this would help a lot.
Good Density for vibration reduction By Jim on 3/8/2015Jim would recommend this product to a friendI bought the small (17'' x 6''). It was big enough to place under my INS135 skimmer/pump with enough left over to place under my return pump. It made a noticable difference in noise level of both.