Double metal seal fitting

A multi-port device such as a thermal expansion valve for an air conditioning system includes a seal structure (10) with a first seal portion (12) and a second seal portion (14). The first seal portion includes a metal material adapted to provide a primary seal. The second seal portion is attached to a free edge of the first seal portion and adapted to provide a secondary seal. The multi-port device with seal structure militates against leakage during operation of the air conditioning system.