P/N 15662 Breather for 1/16? Vacuum/Boost Port. Replacement breather for the vacuum/boost nipple that comes stock in all Aeromotive Bypass Regulators. Perfect for any application that does not require fuel pressure to be influenced by manifold pressure. 1/16? NPT Male threads directly into the regulator vacuum/boost port. Machined from bronze, compatible for installation into aluminum ports. Bronze breather element allows air to move into and out of the regulator cap as needed while stopping dirt and debris from entering the regulator cap/spring housing. Direct replacement for all Aeromotive bypass regulators where needed. Ideal replacement for the vacuum/boost port found in all Aeromotive bypass regulators where Vacuum/Boost reference is not required. Machined from solid brass a 1/16? NPT male thread, this features a sintered brass filter that allows the regulator to breathe but inhibits foreign material from entering the re gulator cap.