Rockwool RXCB11224, ComfortBoard 80 R-6.3 Rigid Stone Wool Insulation Board, 1.5" x 24" x 48", Covers 48 sq. feet, Fire Resistant

I have a roof mounted ac condenser. I used this in the attic, on the inner side of the roof, directly under the ac unit. It quieted the hum by about 50%. Which was aabout what I expected. Rockwool makes a sound batt also, but I could not find it near me. I am happy with the results. Easy to cut using only a serrated knife blade.

Pricey but works well

It's on the pricey side but works well for sound asorbing

Very good product! Very easy to cut and install. Fit very well into my generator shed build. I love the sturdiness. Alittle in the high side as far as cost, but required the heat rating for insulation for a high heat environment!

Material was.a little damaged but still usable.

Can’t find at big box stores thanks