This standard sized pillowcase is 100% silk, not the sub-standard polyester satin found in most department stores. Switching from a cotton pillowcase will help keep your curls intact overnight while you sleep, as they can just glide over the silky fabric. Your hair will be much less frizzy and tangled in the morning than with a traditional cotton pillowcase. Cotton also has a tendency to suck moisture from your hair, so this pillowcase will help keep your hair softer. The dimensions are 20" x 30" and will fit any standard sized pillow.