Matrx Scavenger Autoclavable 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.the 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.