This solid 18 oz. vinyl polyester tarp has a 1/4" galvanized steel chain perimeter so it stays in place during high winds. No need for stakes or sandbags. Vinyl has UV and mildew inhibitors added for outdoor durability. Optional installer device makes storage, installation, and take-up easy.Vinyl Covering: 18oz./sq. yd. fully COATED vinyl on base fabric scrim of 1,000 denier x 1,300 denier polyester. Fabric meets following tests: Tear Strength Tests: Warp 100 lbs., Fill 100 lbs., Grab Tensile Strength: Warp 410 lbs., Fill 410 lbs., Weft Insertion: 18 x 17. Vinyl compounded with UV inhibitors and mold inhibitors. Cold Crack: minus 40 degrees FÂ°.Perimeter Pocket Weight: 1/4" Hot Dipped Galvanized Grade 30 Proof Coil Chain. Material Diameter is 0.276". Working Load Limits 1,300 lbs. Proof Load Test 2,600 lbs. Minimum Breaking Load 5,200 lbs. Inside Length 1.24" Inside Width 0.38" Weight Per Foot 0.63 lbs.