Upgrade your sleep with these Tafts bamboo sheets. This is a complete 4-piece California King set: it includes one fitted sheet, one flat sheet, and two pillowcases with envelope closures (plus a fabric storage bag). They're made from 100% certified organic bamboo viscose, not a blend. The fabric is a 400 thread count sateen weave that feels incredibly silky and smooth – and it actually gets softer every time you wash it. Bamboo is naturally thermo-regulating, meaning these sheets are cooling in summer and breathable year-round. They're also moisture-wicking and hypoallergenic. The fitted sheet has deep, 360-degree elasticized pockets that can handle mattresses up to 17 inches thick, so it stays put. They're OEKO-TEX certified, so they're tested free from harmful substances. Tafts, a company based in Houston, TX, backs these sheets with a lifetime guarantee against defects. For care, just wash in cold water and tumble dry on low. A luxurious, eco-friendly choice for your bed.