Abstract: An improved housing for a condition responsive indicating instrument which includes a one-piece, integrally-formed casing having a generally circular front support plate whose front surface is adapted for mounting a dial face thereon and a cylindrical wall integral with said support plate and extending rearwardly therefrom to form a cavity for housing the internal mechanisms of the instrument. A "blow-out" back cover normally seals the back of the cavity but is responsive to excessive internal pressure to break the seal to relieve the pressure. The back cover overlays a dual function diaphram which both forms the rear seal and compensates for temperature variations. A bracket is coupled, either directly or indirectly, between the rear surface of the support plate and the central portion of the back cover to prevent relative axial motion therebetween.