The Ms. Remi Satin Bonnet is a double-lined satin bonnet designed to protect hair overnight by reducing the friction that causes tangling, breakage, and moisture loss -- a well-established benefit of satin-lined sleepwear across hair types, from coily and kinky textures to straight, wavy, and relaxed hair.
It's worth noting that satin is a weave, not a fiber -- this bonnet's satin is not silk, which is a specific natural fiber with somewhat different moisture-retention properties. That doesn't make the bonnet less useful for its core job of reducing friction against hair while you sleep, but it's a distinction worth knowing rather than assuming satin and silk mean the same protection. It's one-size-fits-all, from Annie International's Ms. Remi line, a long-running hair-protection brand.