Let the sun warm your pool let the blanket keep it warm! Warm your pool fast with a Magni-Clear solar blanket for Rectangular In-Ground Pools. Each of these innovative pool covers is packed with air bubbles that create an insulating layer protecting your swimming pool from chilly winds and nighttime cooling. These tiny cells trap heat so water stays warm even on cloudy days and cool nights. The clear plastic design lets in more sunlight so the warmth reaches deeper for consistent natural heating that surpasses comparable Intex spa covers. Our outdoor blankets are UV-protected and chemical resistant in order to endure years of direct sunlight.