Feel confident in your pool's winter protection with the SilverKing Winter In-Ground Pool Cover. Made with cold weather-resistant materials, this winter cover provides long-lasting performance. The cover securely fits over the entire pool area. Hydrotools By Swimline Silver King line of winter covers feature a solid 12 x 12 scrim thread count material, ensuring no water or debris passes through during the winter season. The covers are also UV & Chemical resistant. Your Swimline cover should be able to naturally float loosely on the water. If you have large top rails, consider going up a size. Tighten the cover so it feels secure around your pool without feeling overstressed.