This is a top cover plate for a Vulcan 880/890 Wheel Lift by Miller Industries. It is bolted down by two bolts. See features for related hardware and see brochures for a reference chart (item #27).
Related Hardware:
(2ea) 1/4"-20 x 1" Bolt (12-0400070)
(2ea) 1/4" Flat Washer (12-0400451)
(2ea) 1/4" Lock Washer (12-0400452)