A pressure-energized, annular metallic seal is provided that includes a central annular portion and a pair of annular leg portions extending from the central portion. Each leg portion includes a convex sealing surface lying in sealing plane. One of the leg portions preferably has an annular flange offset from its sealing plane in an axial direction towards the sealing plane of the other leg portion. One of the leg portions preferably has at least one radially extending tab projecting further than adjacent parts of the seal. The seal is preferably manufactured by first cutting a first annular edge in a metallic sheet material, then bending the sheet material substantially into the shape of the seal, and then cutting a second annular edge to complete the shape of the seal. The second annular edge preferably defines the annular flange and/or the at least one tab.