Sei Flat Sheet

Name: Sei Flat Sheet - Clearance 50
Brand: MATTEO
SKU: 500015X5

100% Cotton | 600 Thread Count | Sateen Weave | Garment-Dyed

$162.50 ~~$325.00~~

Size:

King

Queen

Twin

Quantity:

Variant

Description

Sei flat sheets are finished with a 1/2" hem with a double stitch detail. Darker colors feature a contrasting white top stitch detail.

We recommend using a King flat sheet for a Cal King bed and a Queen flat sheet for a Full bed.

100% cotton
Sateen weave
600 thread count
Garment-washed

Fabric

Sei is our highest thread count fabric at 600 TC. We are not myopically focused on thread count at MATTEO. Thread count is one among many measurements of quality in the world of bed linens. The most simple definition of thread count is to take a pair of scissors and cut out a square inch of fabric and count each individual yarn (or thread). This is the thread count and, as such, thread count is simply a definition of the density of the weave. It does not take into consideration the softness of the raw cotton used or the size and smoothness of the yarn, nor does it measure the balance of the weave. Focusing only on thread count is similar to deciding which beer to drink by only measuring its alcohol content.

We have not yet gone above 600 thread count at MATTEO because higher counts typically produce a stiff and dense fabric that does not move or breathe. All sateens (or satin) fabrics have a face which is softer and a backside which is rougher. This is what creates the "silky" feel that customers love so much. And our customers love Sei because it is one of the purest, softest, and silkiest fabrics on the market.

Care Details

Wash

Wash should be separated into light & dark colors. Do not overload machine as this will damage long cotton fibers. We recommend a lukewarm wash cycle with a gentle detergent & a cool rinse.

Bleach may be used on white cotton bed linens only. Avoid using products that contain whitening agents such as chlorine bleach, alpha hydroxy acids and benzoyl peroxide on garment-dyed items. The reactive dyes used for garment-dyeing are not resistant to these whitening agents.

The largest challenge with garment-dyeing is the truth that it is an art, and not a science. We must allow for a shade variation of +/- 10% from dye-lot to dye-lot.

Learn more about Garment-Dyeing.

Drying

Tumble dry with low heat.Remove bed linens promptly from the machine to reduce wrinkling. For best results, line dry.

Ironing

We at MATTEO tend to prefer a lived-in look, as such, you don't find us ironing our sheets too frequently. If you prefer a crisp looking bed, our cotton bed linens should be pressed while slightly damp using the Lightweight Cotton or Medium setting.

Size

	inches	cm
King	118 x 111	300 x 282
Queen	100 x 111	254 x 282
Twin	79 x 106	201 x 269

Important Notice

All products purchased from the MATTEOX clearance page are samples that might exhibit visible flaws, including, but not limited to, off-color shades, incorrect threads, and faded edges. Products purchased in the same color might be different tones owing to differences from their respective dye lots. All products purchased at 50% to 70% off can be returned for a full refund or store credit. All products purchased at 80% to 90% off can only be returned for store credit. All returns involving a MATTEOX product are subject to a $10 restocking fee.

Frequently Asked Questions

What fabric is the Sei Flat Sheet made from?

The Sei Flat Sheet is 100% cotton in a sateen weave, with a 600 thread count. It is garment-washed, which gives it a silky hand feel from the first night. The sateen construction means the face of the fabric is noticeably softer and smoother than the reverse, which is what produces the signature silky feel.

Is a 600 thread count sheet actually better than lower thread count options?

Thread count measures only the density of the weave. It does not account for the softness of the raw cotton, the size and smoothness of the yarn, or the balance of the weave. At MATTEO, 600 TC is our ceiling by design: counts above 600 tend to produce a stiff, dense fabric with reduced breathability. The Sei uses the same 120/2 Ne yarn in both warp and weft, which is where its softness comes from, not the number alone.

What size flat sheet should I order for a California King or Full bed?

For a California King bed, order the King flat sheet, which measures 118 x 111 inches (300 x 282 cm). For a Full bed, the Queen flat sheet at 100 x 111 inches (254 x 282 cm) is the right fit. The Twin flat sheet measures 79 x 106 inches (201 x 269 cm).

How should I care for the Sei Flat Sheet to keep it looking its best?

Wash lights and darks separately in a lukewarm cycle with a gentle detergent and a cool rinse. Do not overload the machine, as heavy loads can damage the long cotton fibers. Tumble dry on low heat and remove promptly to reduce wrinkling; line drying gives the best result. If you prefer a crisp finish, press the sheet while slightly damp on the Lightweight Cotton or Medium iron setting.

Can I use bleach on the Sei Flat Sheet?

Bleach is safe only on the white colorway. On all garment-dyed colors, avoid any product containing chlorine bleach, alpha hydroxy acids, or benzoyl peroxide. The reactive dyes used in garment-dyeing are not resistant to those whitening agents, and exposure will cause color loss. For more detail on why, see our garment-dyeing guide.

What finishing details does the Sei Flat Sheet have?

The Sei Flat Sheet has a 1/2-inch hem with a double-stitch detail. On darker colorways, that hem stitch is done in contrasting white thread, giving each sheet a clean, tailored edge that reads well on a made bed.

How does the Sei Flat Sheet compare to MATTEO's other luxury cotton bedding?

Sei is MATTEO's highest thread count fabric at 600 TC, making it the most substantial cotton option in the collection. Customers who want a silkier, denser hand feel tend to prefer Sei, while those who want a crisper, lighter feel often choose the Washed Sateen or a percale-weave option. All MATTEO cotton fabrics are garment-washed and dyed using non-toxic dyes, and all are designed and manufactured in Los Angeles.

Is the Sei Flat Sheet a good choice for people with sensitive skin?

The Sei Flat Sheet is 100% cotton with no synthetic blends, and all colors are dyed using non-toxic reactive dyes. The garment-washing process removes surface starch and roughness before the sheet reaches you, so the fabric is soft against skin from the first use. Customers with sensitivity to synthetic fibers or harsh chemical finishes consistently find cotton sateen at this construction level comfortable for daily sleep.