G727 grant continuity card
From Computer History Wiki
The G727 grant continuity card (known to many as the 'knuckle-buster') was very small card (single width, but only approximately half the standard length) which plugged into an SPC slot or MUD slot in a UNIBUS backplane in an otherwise-empty slot, and carried the bus grant line signals through the slot.
It carried only the BG4-BG7 grant lines from the 'in' pins to the 'out' pins. Since it contained no components, and had no handle, it could be used in slots which did not have the usual amount of space available (such as the MM11-D core memory).
