Size:Set of 13 Extremely high quality. Beautiful patterns and colors. It's full, 50 ounce per square yard fiber face weight keeps the tread looking beautiful for many years to come. They won't, "ugly out" like low weight treads. Each tread has rounded corners. The size is 24" x 8" and the thickness is 3/8". Why should I choose these carpet stair treads over other carpet stair treads? •Our carpet stair treads are manufactured with a full 50 ouce per square yard fiber face weight. Any time experts compare carpet products they always compare the fiber face weights. Fiber face weight refers to how much fiber is tufted or needle punched into one square yard of material. Its kind of like comparing thread counts of fabrics. Don't buy any carpet product until you have asked the seller about the face fiber weight because higher weights will ALWAYS out last lower weights. Our carpet stair treads are designed for extremely heavy traffic and will not show wear for a very long time. They will outlast any other carpet tread on the market. •Our carpet stair treads are made of 1st quality materials with ZERO defects! •Our carpet stair treads are manufactured from running line styles and colors. Which means we only offer styles and colors that interior decorators and designers love. Each stair tread comes with two strips of specially designed removable adhesive for indoor use. The installation is very simple. Carefully remove the release paper liners. Loosely position the tread. Then firmly press the tread to the step. If you need to adjust the tread simply lift the tread and reposition. The adhesive is intentionally designed with a low peel strength but a very high shear which means the tape prevents the tread from shifting. If you want to remove the tape from the tread simply peel it off slowly. It is possible that the adhesive could leave a residue which in most cases can be removed with a damp cloth.