I bought 3 brands of butyl sound deadener to see which one lived up to the hype and the best value. Measured a random sheet out of each box with calipers in 20-30 spots around the sheet, then weighed on a digital scale. - Vevor 80 mil butyl is 80 mil thick average. Sheet weighs 10.87oz and is 145sqin (10\"x14.5\"), which calculates to 13.4sqin per ounce. This was the heaviest butyl of the bunch, nice and sticky, no noticed odor. Installing this sound deadener. - Kilmat 80mil butyl is 80 mil thick average. Sheet weighs 8.2oz and is 160sqin (10\"x16\"), which calculates to 19.5sqin per ounce. Sticky, but weighs the least and I could notice an odor while handling it. Sending back. - Uxcell 80 mil butyl is actually 65 mil thick average. Sheet weighs 9.67oz and is 151sqin (9.75\"x15.5\"), which calculates to 15.6sqin per ounce. This was the least sticky of the bunch, probably poor adhesion as mentioned in another review, no noticed odor. Sending back. (65 mil = false advertising?) As for sound deadening qualities I'm not sure how Vevor will compare to Kilmat, but Vevor is heavier and it's less expensive.