R-1219/TN410 PRR-12 Surveillance Receiver

Rare portable VN-Era surveillance receiver, R-1219/PRR-12 with TN-410 tuning unit that covers ~933-1566 MHz. AM/FM/CW/SSB, wide/narrow audio bandwidth, 75KHz wide/13KHz narrow IF bandwidth. TNC VEE antenna inputs (omni?) and BNC DF antenna input. Odd design in that the receiver 'mainframe' is the bottom half of the box, and the tuner module is the whole front panel assembly with the controls and all. It mates to the mainframe via an amphenol connector and an SMB coax connector.
Certainly a rarity, can't find any mention of it online!
includes battery cable, for external battery pack. Seems to run on 9-12vdc. $1500