Rug Settler Slip Resistant Anchor Pins to secure a rug or sheet over a carpet. Avoid tripping over a rug that is placed over a carpet. The transparent top is designed with rounded margins to make it user-friendly. IF YOUR RUG IS TOO THICK or with the acrylic base and “rug settlers” needle is unable to pass through it, you can hold the needle portion with a nose plier and press it firmly. You can also make the tip a little hot to pierce it easily through the acrylic base of the carpet. DO NOT USE this product if there is a danger of kids who can pull it out and get injured, although it gets firmly engaged and not easily pulled out. Do NOT USE this product if there is a danger of elders who can still get caught their feet and trip. Although its thickness over the rug is 2.5mm that is only one-tenth of an inch. Please make sure the combined thickness of overlay and underlay do not exceed a total thickness of 1 inch, as our rug settlers work best for that thickness. If the thickness of overlay 0.75 inches and the thickness of underlay is also 0.25 inches, these settlers would work fine and will fit in well. If the thickness of both the layers is less than 1 inch, it will not fit in well and will give a bulge.