One tree mat provides 9 square feet of weed-free soil and all of the water and minerals that weeds usually take. UV stabilized with carbon black for three years of weed control. 2.5 Mils thick (400 micropores/in2). Use ground staples (sold separately) to anchor tree mats. Place with dull, rough side down and shiny side up. Bundle of 100 mats (3’ x 3’ each).