YANIBEST Satin Bonnet for Sleeping, Hair Bonnets for Women and Men, Double Layer Ajustable Silky Bonnet for Curly Braids Hair

Q: Will this sleeping cap large enough to cover a bun on top of my head?

I think it will because there's an adjustable draw string to tighten it around your head.

Q: Will the XL fit a 24" head comfortably? I don't want to wake up with a headache.

Absolutely. This cap is naturally very loose. Use the drawstring to tighten it to your preference. I recommend using a satin scarf to protect the perimeter of your hair, then apply the bonnet. Otherwise, avoid making the drawstring snug.

Q: What’s the material of this sleep cap?

It's kinda like poly satin. Very silky feel to it. I bought another because I love how it keeps your curls in place. I've bought other types but this one is to me the best yet

Q: what are the washing instructions for this cap? I got the light blue one back when it was in stock but I never washed it.. is it machine washable?

the info on the product page says "This fabric structure can stand up to machine washing on gentle cycle in cold water (lay flat to dry). However, to maximize the life of the product, I recommend hand washing and air drying. Do not twist or wring tightly. Instead, squeeze out excess water with a towel then air dry."