MIL-PRF-85726B, PERFORMANCE SPECIFICATION ENCLOSURE, STANDARD AVIONICS, FORCED AIR-COOLED, SPECIFICATION FOR (15 JUL 1998) [SUPERSEDING MIL-E-85726A (AS)]., This specification covers forced air-cooled standard avionics enclosures, hereinafter referred to as enclosures. The enclosures accommodate Standard Electronic Modules (SEMs) Format B Span 2, Format C, and Format E, and a standard backplane.