1.Unique Design: This gripper uses VACUUM TECH design which grips hard smooth floors firmly and easily, this design can protect your floor perfectly as no glue used on floor. But it does not work for rug on carpeted floor. It does not work for rubber backed rug ,jute rug or fluff backing rug. 2.Design Feature. This product can easily be glued under rug. The side facing the floor features tiny suction pores. These pores utilize the VACUUM TECH feature in which whenever pressure is applied from the top, air escapes and creates a low-pressure region within the cups. This produces an adhesive effect, which keeps your rug in place. 3.Advantages. The rug anti curling gripper is less than 1/10 inch thick and inconspicuous after installing. Suction technology firmly sticks to the floor without causing marks or damage, and the gripper easily peels off the floor. It is convenient to wash, as you won't have to separate it from your carpet for cleaning. The tape for rug adds extra comfort underfoot owing to the slightly bouncy nature of suction technology. 4.Components. This package includes 4 pieces. The size of the gripper is 3.9inch x 3.9inch. Each piece is square in order to increase the surface area in with the floor. That leaves your kitchen, bathroom, and hallway much more secure. You can even use them outdoors to prevent slipping and flatten corners.