This is the cage plate of the recovery boom on light duty wreckers by Miller Industries. They are located on the top, inside of the outer stinger. See Brochures for reference charts and Features for related parts. This cage plate will fit on the following wreckers: Century 400 & 600 Series and Vulcan Modular 880/890 Series.
Related parts:
Wear Pads(896040002)
Outer Stinger Weldment (12-0807474)