Covertech Solar Cover Blanket Thermo-Shield, 12 ft Round - 4-Year - Blue/Black - SL-1310SKU:10001746
It's too early to say if it will last 4 years. It's not the thickest solar blanket out there is but for the price, it does the job. My 12' above ground pool was at 25c, covered it at the end of the day, it was 14c outside overnight, checked the water in the morning and only lost 2 degrees. Not bad at all.