A modified Gemini suit manufactured by the David Clark Manufacturing Co., the overall assembly consisted of a constant-wear garment and a pressure garment assembly. Crew members would also be provided with coveralls to wear in a pressurized cabin as desired. The primary functional requirement of the Block I suit was to provide environmental protection in a depressurized CSM cabin. Therefore, it did not incorporate a thermal and micrometeoroid-protection garment or the helmet visor assembly, which were required for extravehicular operation. The memo listed seven major modifications required to adapt the Gemini suit to make it acceptable for use as an Apollo Block I item.