· Sturdy & Durable Non-Woven Fabric: The mulch rings are made of sturdy and durable non-woven fabric and of a good thickness that prevent the sunlight from entering into the soil but let air and water through to retain soil moisture.6 x 1.5 inches (W) x 12.0 ounces 12 Pcs Non-Woven Tree Mulch Ring Degradable Tree Protector Tree Weed Barrier Mat Black 12.