Partyline: What are the CC-75 and CC-240 Headsets?

The CC-75 and CC-240 are obsolete dynamic headsets that Clear-Com provided in the late 1980s and early 1990s that were and still are compatible with Clear-Com RS-100, RS-500 and RS-600 series beltpacks. (Alternative headsets in the current range are CC-95 and CC-260 headsets)
The CC-75 was a single muff dynamic noise cancelling mic headset, the earphone / mic was a light blue color.
The CC-240 was a dual muff dynamic noise cancelling mic headset, the earphones / mic were a light blue color
The pinouts were to a 4-pin XLR F,
pin 1 - mic lowpin 2 - mic high
pin 3 - headphone lowpin 4 - headphone high