Split Top King Sheet Set (Flex) vs Split King 600 Thread Count Cotton Sheets

Buy the 600 thread count cotton set for a true split king adjustable bed, where each half of the mattress moves on its own. Buy the 1800 series flex-top set only if your mattress has a split head and a connected foot. The cotton set is the better fabric: long-staple cotton in a sateen weave feels smoother and breathes better than microfiber, and owners call it substantial. The flex-top set wins on fit for flex-top beds and has far more ratings, but its 1800 figure is a multi-ply yarn count, not a true single-ply thread count.

• Choose the Split Top King flex set if your adjustable mattress is split at the head but joined at the foot, or you want wrinkle-resistant microfiber that needs little ironing.
• Choose the Split King cotton set if your adjustable bed has two separate Twin XL mattresses that move independently, or you prefer the feel of real long-staple cotton.