1. High performance vacuum suction cup with 8 inch diameter is sturdy and durable for quick absorption on smooth, flat, non-porous surface. 2. It is ideal for lifting and moving glass, tiles, refrigerators, furniture, plastic, metal, slate and household appliances. 3. Please note that it is not suitable for adsorption on tiles with uneven surface. 4. The ABS plastic handle of the suction cup is ergonomic, strong and comfortable, with excellent anti-slip effect.The suction cups have very strong suction and can operate at temperatures ranging from -20°C to 60°C and are kept under vacuum for 4 hours. 5. The maximum vertical suction of a single suction cup is 220 pounds.The suction cups have been specially developed for curved surfaces.Suction cups provide plenty of space.It can lift curved objects such as bathtubs, washing machines, etc.and can also be used on flat surfaces.All you need to do is place the suction cup on a smooth, non-porous surface or flat surface.Then pump the vacuum into the suction cup until the red warning line disappears.A red line on the indicator alerts the user that the seat cushion is losing vacuum.When the red line appears, just pump the plunger with your thumb without removing the suction cup from the object surface, so that the suction cup can hold the object surface firmly for a long time.