Iron Gate - Gatekeeper Doormat 18x30 Light Grey - Extremely Sturdy and Rugged Construction 69 Ounces / 6000 GSM - Polypropylene Surface & Rubber Back for Better Floor Grip - Indoor/Outdoor use Iron Gate Gatekeeper Doormat 18x30 Grey with Black Rubber border. Polypropylene surface with nubbed Rubber back to hold in place and prevent sliding. Raised ridge deigns captures dirt and water Unique "Raised Rubber water dam" border keeps dirt and water in the mat and off the floor, minimizing slip hazards and floor damage. Exclusive ridged construction is very effective in storing dirt and moisture beneath shoe level. Exclusive rubber reinforced face nubs prevent pile from crushing in high traffic areas Recycled Rubber backing - easy to clean and maintain Compare our quality against any similar mats and you will be highly pleased with your purchase. Each mat measures 18 inches X 30 inches X 3/8 inch thick and weighs 69 Ounces or 6000 Grams per Square Meter.