RTS BP-351 Two-Channel Beltpack

RTS BP-319 BLK Single Channel Beltpack with 5-pin female headset receptacle

TELEX RTS BP-318 4-Pin Single Channel Two-Wire Intercom BeltPack

Clear-Com CC-95 Intercom Systems Single-Muff Headset vintage untested

Production Intercom MSM-1 - Please Read

ASL BS17 Single-Channel Beltpack, Tecpro/Clearcom/Stonewood Compatible

RTS Telex BP325 Portable Headset Station 2-Channel Intercom Beltpack

RDL FP-UBC2 Unbalanced-to-Balanced Audio Converter.