The Five 5ided Smooth mattress protector helps prevent the development of asthma and features the laboratory-certified H2Pro liquid-proof membrane on five sides of the mattress. With microscopic pores to allow air passage, the H2Pro layer completely blocks liquids, viruses, dust mites and allergens. Unlike other bed protectors that sound like a plastic bag and don't cover the whole mattress, the Five 5ided protector is quiet and includes the universal fit elastic ensuring a secure fit for mattress depths 6�-22�.