Arctic Armor Air Equalizer Pillows act as an ice compensator and absorb the pressure from freezing water helping to protect your above ground pool's walls. This heavy duty vinyl air pillow reduces excessive center accumulation of rain, snow, and leaves on your winter cover. These 4 foot by 8 foot winterization air pillows inflate easily and are made of tough gauge vinyl. Air pillows collapse inward to absorb the pressure caused by ice.