Designed for heavy-duty indoor and outdoor use, the anti-vibration pads bear a load of up to 800 pounds on all 4 pieces. The two rubber pads on the top and bottom are anti-skid. Non-slip. Easy installation, all you need to do is insert the "leg" holes of the outdoor or indoor unit into the screws and tighten the nuts. You can use the pads inside balconies or roofs, even on walkways, and it won't look bulky at all. Isolates vibration transmission and reduces low-frequency noise caused by vibration. Note: The data is all measured manually, please allow 1-3cm error due to light and display difference, there may be color difference, please refer to the actual item received.