in canada that is called a cheater vent ,because of the 2 large holes and rubber diaghram it is not approved if being inspected , and what we call an auto air admittance valve will have several small openings around the whole dia and will have a diaghram that is made out of a siliconized rubber ...
in canada that is called a cheater vent ,because of the 2 large holes and rubber diaghram it is not approved if being inspected , and what we call an auto air admittance valve will have several small openings around the whole dia and will have a diaghram that is made out of a siliconized rubber ...