A system for sealing components of an exhaust system in an engine system comprises a bellows with an elongated portion. A flange is coupled to the elongated portion, the flange comprising a first portion and a second portion. An extended portion extends between the first portion and the second portion, the extended portion defining a gap and having a cross-sectional shape different than the first portion and the second portion. A connector is configured to couple an aftertreatment system to the flange. The connector comprises a sealing surface adjacent to the flange. A sealing component is sized and configured to fit partially within the gap and contact the sealing surface to create a seal between the extended portion and the sealing surface.