Porter - Matrx Scavenger Autoclavable Nasal Hoods Adultthe most efficient traditional dental nasal hood for scavenging waste nitrous oxide. Nasal hoods adult The soft and pliable inner liner creates a tight, yet comfortable seal around the patient? s nose ? thus assuring the Porter mask? s superior scavenging efficiency. The Porter double mask is non latex and made from durable yet soft silicone rubber. Adult and pediatric sizes are available.