MB-1 & 2 were experimental test pilot's partial pressure suits using the K-1 helmet. Chest and abdominal bladders were added to produce the G4A anti-G suit for the Air Defense Command, which provided 5-6 protection to 30 km, used no capstans, and with the MA-1 helmet rather than the K-1.

• 487 - Sears, William J, A Historical Review of Partial and Full Pressure Suits, . HTML when accessed: http://webpages.charter.net/mcelwain/PSUITS-Chronology.htm