Onion......that's actually not a tarp at all.....this is the bottom of a buddies pool that had the inflatable sides, some neighbor kids shot the sides with a bb gun and he was gonna get rid of it. Gotta be at least 45 mil. thick it's very heavy....LOL
I even took the sides and cut then up, gonna use them in the flower beds to keep the weeds away...tried that crap they sale and it doesn't work.