Switching from a cotton pillowcase will help keep your curls intact overnight while you sleep as they can just glide over the silky fabric. The ONLY fabric you should be sleeping on is silk.
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.
This standard sized pillowcase is 100% quality silk, not the sub-standard polyester satin found in most department stores. It's 20" x 30" and will fit any standard sized pillow.