PelletVent Pro is engineered with features for a durable, safe, and aesthetically pleasing venting system. PelletVent Pro features a metal-to-metal seal as the primary protection against leakage. A high-temperature silicone O-ring, completely encapsulated between the inner and outer walls, provides a secondary seal. The patent-pending superferritic metal inner liner is proven to be the most corrosion resistant. According to the company, this product line has, by far, the best-performing metal systems to use when burning biofuels.