OT: Who made this Vacuum Tube Flip Flop Monostable Multivibrator (1955) & ...

[Ar9100]

Apologies:
OT: Other.

What Company made this Vacuum Tube Flip Flop Monostable Multivibrator (ca. 1955 ?) & what machine was it used in ?

FF-2 DRA34376 09975 7-5-55

It looks too new to be Whirlwind, ( definitely newer than Colossus, Bombe, Einiac ). And also a bit newer than Univac 1103 and the IBM 703 (?).

A prototype ?
Could "DRA" = Draper Labs ( or some MIT collaboration ? )

There are several versions: FF-1, FF-2, FF-4, so different vacuum tube monostable multivibrator Flip Flops, having different logic functions.

Anyone know, or know someone who might know ?
thank you,