It is a semi-circular grounding fitting that has 2 screws and can be retro-fitted around wires already installed in conduit by loosening the locknut and inserting the wedge between the locknut & the box. The screws are then tightened to effect a bond.
BTW,
I am not referring to bonding locknuts or bonding bushings.
Joe T. may be able to provide a picture(exhibit).
