A protective organic cotton dust mite barrier cover to keep your twin xl mattress safe! Heat pressed to keep the pores so small that dust mites can't get through! As you wash it the weave gets tighter and tighter so it lasts a very long time. The organic cotton has a cooler feel than polyester due to its natural breathability. Undyed. Softens further after washing. Machine wash and dry on regular. Add 1/4 cup of vinegar to the load to increase softeness. Fabric is not pre-shrunk and will shrink to the proper size once washed and dried. Barrier cover has a zip closure to ensure complete protection. Made here at our San Diego, CA Facility. Ships within 1-2 business days.