Sei Fitted Sheet

The Sei Fitted Sheet is 100% cotton in a sateen weave, garment-washed to a 600 thread count. Sei is MATTEO's highest thread count fabric, woven with 120/2 Ne yarn in both warp and weft, which gives the face of the sheet its characteristic silky hand. The garment-washing process softens the fabric before it reaches you, so it arrives ready to use rather than stiff from finishing.

Thread count measures only the density of the weave; it says nothing about the quality of the raw cotton, the yarn size, or the balance of the construction. MATTEO has not gone above 600 thread count because counts beyond that typically produce a heavy, dense fabric that does not breathe or move well. Sei reaches 600 TC without those trade-offs because the yarn quality and weave balance were prioritized alongside density. A well-constructed 400 TC sheet in long-staple cotton will outperform a poorly made 1,000 TC sheet.

The Sei Fitted Sheet has 16-inch pockets and fits mattresses up to 20 inches deep. Each corner is finished with a flat felled seam tacked at the top corner to reinforce the areas that take the most stress during fitting. The elastic band spans the entire perimeter of the sheet and is encased in a high-density stitch, so it holds its tension through repeated washing.

The Sei Fitted Sheet is available in Twin (39 x 75 x 16 in.), Twin XL, Full (54 x 75 x 16 in.), Queen (60 x 80 x 16 in.), King (78 x 80 x 16 in.), and California King (72 x 84 x 16 in.). All dimensions include the 16-inch pocket depth. If you are pairing with a flat sheet or pillowcases, the full Sei collection is available at matteola.com/collections/sei.

Wash the Sei Fitted Sheet in lukewarm water with a gentle detergent, separating light and dark colors. Do not overload the machine, as this puts stress on the long cotton fibers. Tumble dry on low heat and remove promptly to reduce wrinkling; line drying gives the best results. For garment-dyed colorways, avoid chlorine bleach, alpha hydroxy acids, and benzoyl peroxide, as the reactive dyes are not resistant to those whitening agents.

Garment-washing means the finished sheet is washed as a complete product rather than treating the fabric before construction. This process relaxes the fibers and breaks in the hand of the cloth, so the sheet arrives soft rather than requiring multiple home washes to reach its best feel. It also produces a slight dimensional variation in texture that gives MATTEO cotton its lived-in quality. You can read more about MATTEO's garment-dyeing process at matteola.com/garment-dyeing.

Sei is MATTEO's highest thread count cotton, at 600 TC in a sateen weave, with a silky, smooth face and a slightly heavier hand. The Tru Fitted Sheet is a percale weave with a crisper, matte finish and a lighter weight, which many hot sleepers prefer. The Nap Fitted Sheet offers a different texture and weight for those who prefer a more relaxed cotton feel. If you want to compare fabrics before ordering, MATTEO's 600 Thread Count Cotton Fabric swatch is available separately.

The Sei Fitted Sheet is 100% cotton with no synthetic blends, and it is dyed using non-toxic reactive dyes. The garment-washing process removes residual finishing chemicals before the sheet reaches you, which reduces potential irritants common in untreated fabrics. The sateen weave places the smoothest face of the cloth against the skin, minimizing surface friction. Those with particularly reactive skin should wash the sheet once before first use with a fragrance-free detergent.